View source for Backup/Causes of data loss

Causes of data loss include device failure, software bugs, software lock-in, and human error.

== Hardware failure ==
The magnetic head that floats close to a hard disk's metal platters could [[:w:head crash|crash onto it]], the spinning motor's lubrication could wear down, a manufacturing defect could lead to early defect, or a storage controller could malfunction due to a voltage spike caused by a malfunctioning power supply or a lightning strike.

Since RAID storage systems are more complicated, they have more points of vulnerability, such as a malfunctioning controller that could damage data even if the individual drives are working well, or a drive failure poking holes over the entire data stored on the system due to lack of redundancy drives.

This happens because RAID systems typically stripe data across drives to multiply sequential transfer rates, since it allows the individual drives to work in parallel. This performance benefit comes at the cost of vulnerability to data loss, thus requires redundancy drives (or "pairity drives") so the user can swap out a defective drive, and data can be automatically restored on a functional drive. If affordable, RAID network attached storage is for convenient quick access to a large pool of data, but a separate [[:w:cold data|cold storage]] copy that is rarely touched should be kept if the goal is long-term archival.<ref>[https://www.youtube.com/watch?v=gSrnXgAmK8k ''All of our data is GONE!''] – [[:w:Linus Tech Tips|Linus Tech Tips]] – January 4th, 2016</ref><ref name=backblaze20200607 />

The complexity of RAID storage systems also makes it more susceptible to maintenance errors.<ref>{{cite web |url=https://louwrentius.com/scrub-your-nas-hard-drives-regularly-if-you-care-about-your-data.html#fnref:raid6 |title= Scrub Your NAS Hard Drives Regularly if You Care About Your Data |date=2020-04-22 |access-date=2023-01-21 |website=Louwrentius.com }}</ref>

== Software bugs ==
Users have reported parts of their mobile phones' internal storage to becoming inaccessible,<ref>[https://forum.xda-developers.com/t/omnia-2-doesnt-recognize-internal-storage.772641/ ''Omnia 2 doesn't recognize internal storage!'' – XDA forum user ''WhiteRussianBC'' – September 2nd, 2010]</ref><ref>[https://forum.xda-developers.com/t/my-memory-8gb-on-ominia-ii-gt-i8000l-has-disappeared.678991/ ''"My Memory" (8GB) on Ominia II (GT-I8000L) has disappeared!'' – XDA forum user ''mattbiondi'' – May 10th, 2010]</ref> folders disappearing during a move,<ref>[https://support.google.com/photos/thread/106201?hl=en ''Photos disappeared after moving to another device folder'' – Gökhun Güneyhan – Google Photos community (April 24th, 2018; 57 replies)]</ref> bogus software updates rendering devices inoperable,<ref>[https://www.youtube.com/watch?v=FeUBdMU2qA0 ''Apple iOS update BRICKS repaired iPhones after screen repair'' - Louis Rossmann (2018-04-10)]</ref> faulty [[:w:colourspace|colourspace]] conversion causing the operating system to crash in perpetuity,<ref>[https://www.youtube.com/watch?v=iXKvwPjCGnY ''How THIS wallpaper kills your phone'' (by Arun Maini, Mrwhosetheboss, 2020-06-04)]</ref> and all contents of their internal storage being deleted.<ref>[https://www.reddit.com/r/Android/comments/16e6kc/i_just_deleted_a_random_folder_in_my_internal/.compact ''I just deleted a random folder in my internal storage and it wiped my internal storage. What the heck just happened?'' – Reddit – /r/Android (January 11th, 2013)]</ref>

Data stored on the memory card is less likely to get lost, since a memory card can be ejected and read externally, as well as being recoverable to some extent using forensic software.

Should a failure such as a system crash or exhausted disk space occur while a file is being written to, the file might be truncated (partially cut off) or blanked. If the file is still opened in the program (for example, text editor), it can be saved on a different device or partition to prevent loss.

Another way to prevent it is creating revisions in separate files by occasionally changing the [[file naming|file name]] while saving. This can be an incremental number or time stamp.

== File system modifications ==
=== Partition management ===
Partition management is a highly risky task.

Before partitions on a data storage device are modified, a full-disk image backup should be taken, since any interruption in the process could destroy the file systems, making the files inaccessible. A full-disk image backup allows for recovery by writing the partitions in their state before the partitioning back to the device.<ref>{{cite web |website=Reddit |date=2022-11-14 |access-date=2023-01-15 |author=islaambaduk_ |title=3 years of data wiped clean*accidentally* |quote=Was partitioning the drive in cmd and the shit happened |url=https://www.reddit.com/r/DataHoarder/comments/yuz10m/3_years_of_data_wiped_cleanaccidentally/.compact }}</ref><ref>{{cite AV media |url=https://archive.org:443/details/youtube-NtxPrIFpDsk |author=éclairJess |date=2018-08-30 |language=de |access-date=2024-03-20 |title=WICHTIG !!EINSELF! (wird später gelöscht)  |website=Internet Archive }} (originally uploaded to YouTube) - Artist explains she accidentally lost a partition containing her works.</ref>

=== File system repair tools ===
Tools such as [[:w:CHKDSK|check disk]] on Windows and [[:w:fsck|file system consistency check]] on Linux intend to repair problems with a file system that could arise after writing to disk was interrupted, which could, for example, lead to inconsistencies between the files and the space marked as used. On Windows, CHKDSK also renames and relocates files with names containing characters Windows considers invalid such as colons and question marks that might have been created on a Linux-based operating system.<ref>[[Wikipedia: CHKDSK]]</ref>

It is recommended to renew the backup before running such tools, since they are not guaranteed to repair a file system successfully and might cause collateral damage. File system repair can be thought of as a digital surgery. Similarly to partition management, an interruption in the process can lead to enormous damage.

However, on [[:w:journaling file system|journaled file systems]] such as NTFS (default on Windows and widely pre-formatted on external drives) and ext4 (default on Linux) and UDF (optical discs), file system checking is usually not needed after a power interruption, and when it is, it is more reliable than on old-fashioned file systems such as FAT32 that lack a journal.

== Human error ==
Human errors that can lead to data loss include the deletion of files and folders that one thinks are already backed up but are not, mistyping a command, choosing a wrong device for writing a disk image to, and dropping a device from a height or into liquid.<ref>[https://www.youtube.com/watch?v=wDYiJRhzXY0 Alles weg - Hochformat (Simon Unge), January 29th, 2020] – smartphone (iPhone XS plus or iPhone 12 plus) stuck on boot screen after falling from a height of several metres onto a carpet. The carpet did cushion the impact, but not enough to prevent damage to the device.</ref><ref>[https://m.youtube.com/watch?v=DVQ1azBUCAI&list=PLkSXFFvjIepOfrbF4fo2y__0xcYGytbYa&index=14&t=2m54s Prank geht schief – BibisBeautyPalace (Bianca Heinicke), December 15th, 2016 (at 2 minutes and 54 seconds)] – smartphone (iPhone 6s) dropped into pool. Afterwards, it powered on but the touch screen was unresponsive to input.</ref><ref>Smartphone fell into lake, resulting in the loss of all data: {{cite AV media |url=https://www.youtube.com/watch?v=pyh1SgMxEZs&t=03m05s |title=Sony Xperia Tablet Z - Eintauchen und Eintauschen |date=2013-05-23 |access-date=2023-06-10 |author=GO2mobile |language=de }} (at 3 minutes and 5 seconds)</ref>

A damaged touch screen of a smartphone after a drop might be insensitive to touch, making it impossible access files. Even when the smartphone is connected to a desktop/laptop computer through a USB cable or wirelessly, the file transfer typically needs to be activated on the phone first, which is impossible if the touch screen is unresponsive.<ref>[https://forum.xda-developers.com/t/q-get-data-from-cracked-nexus-4.2993942/ Get data from cracked Nexus 4  - Panomosh - January 5th, 2015 - XDA developers]</ref>

Before working with sensitive tools such as <code>dd</code> and <code>ddrescue</code>, it is recommended to renew the backup and to unplug any momentarily unneeded external storage devices to protect them from overwriting accidents.

Avoid working with sensitive tools when tired. Fatigue and sleepiness increase the chance of accidents occuring.

On defective devices, data stored on a memory card is likely retrievable externally, therefore storing data on a modular memory card protects against data loss. The most popular memory card format in portable devices is [[:w:MicroSD|MicroSD]].

Human error is also a risk to [[#Overreliance_on_online_services|cloud storage services]], albeit smaller than the risk of data loss on local data storage managed by an individual with little experience in using computers.<ref name=schneier-201409>{{cite web |url=https://www.schneier.com/blog/archives/2014/09/security_trade-_2.html |title=Security Trade-offs of Cloud Backup |date=2014-09-25 |author=Bruce Schneier |access-date=2023-12-03 }}</ref> For example, Amazon claims their "Glacier" service is "99.99999999999% durable". That is 99 followed by eleven nines, meaning the chance for data loss is claimed to be one in a hundred billion. Even if this claim were true from a technical point of view, which is very unlikely, it does still not take into account that an angry employee could memory-hole data. Though unlikely, it can be safely assumed to be likelier than a hundred billionth.<ref>{{cite web |url=https://www.enterprisestorageforum.com/news/cloud-storage-marketing-hype-amazon-glaciers-big-claims/ |title=Cloud Storage Marketing Hype: Amazon Glacier’s Big Claims |date=2012-09-04 |access-date=2023-12-03 |website=Enterprise Storage Forum |author=Henry Newman }}</ref>

== Vulnerable storage location ==
Some people make the mistake of treating the internal storage of their computer or mobile phone as a permanent archive.<ref name=davdreamer /><ref name=MatHonan>{{Cite news|url=https://www.wired.com/2012/08/mat-honan-data-recovery/|title=Mat Honan: How I Resurrected My Digital Life After an Epic Hacking|last=Honan|first=Mat|date=2012-08-17|work=Wired|access-date=2023-02-06|language=en-US|issn=1059-1028}} "Had I been regularly backing up the data on my MacBook, I wouldn't have had to worry about losing more than a year’s worth of photos, covering the entire lifespan of my daughter, or documents and e-mails that I had stored in no other location." "And worst of all, my AppleID account was broken into, and my hackers used it to remotely erase all of the data on my iPhone, iPad, and MacBook."</ref><ref>{{Cite web|url=https://discussions.apple.com/docs/DOC-6031|title=Methodology to protect your data. Backups vs. Archives. Long-term data protection - Apple Community|date=2014-06-14|website=discussions.apple.com|access-date=2023-02-06}} "No computer, regardless of HD or SSD size is a data storage device, and should never be considered as such." "All collections of media files such as pictures, music, and videos, unless directly needed should be kept off the notebook and on an external hard drive or likewise."</ref><ref>{{cite web |url=https://blog.vellumatlanta.com/2016/05/04/apple-stole-my-music-no-seriously/ |url-status=dead |archive-url=http://web.archive.org/web/20160505014358/https://blog.vellumatlanta.com/2016/05/04/apple-stole-my-music-no-seriously/ |archive-date=2016-05-05  |date=2016-05-04 |title=Apple Stole My Music. No, Seriously. |quote=I painstakingly imported from thousands of CDs and saved to my computer’s internal hard drive. }}</ref>

There is nothing wrong about having redundant copies of files on such devices, and it is useful if accessed frequently. However, without an independent [[:w:cold data|cold data]] backup, files stored on a device's internal storage are at risk of loss from any failure that would make the computer inoperable, ranging from malware, bogus updates, to component failure.

Some vendors of computers and smartphones let the user remotely erase their device if linked from an account, which is intended for use after physical theft. However, this leads to a risk of data being erased through a compromised account.<ref name=MatHonan />

== Bad user interface design ==
Bad user interface design such as the ability to delete photos through a side-swiping gesture on some mobile photo viewers, or the ability to delete history items with a press of the "<kbd>delete</kbd>" key without confirmation on the Firefox web browser could cause the inadvertent deletion of data.

== Software lock-in ==
People might habitually store data inside a locked-in location such as a mobile phone application's internal data, thinking it will always be there. In reality, access to that data could be denied with little warning through a software update that removes a feature, or a software bug.<ref>{{cite web |url=https://www.reddit.com/r/whatsapp/comments/sfi0kp/whatsapp_deleted_all_my_videos_of_a_passed_loved/.compact |title=Whatsapp "deleted" all my videos of a passed loved one. Panicking. |date=2022-01-29 |access-date=2023-01-14 |quote=A person close to me recently passed away and a lot of messages, voice messages, pictures and videos in our conversation were saved on the app and meant a lot to me. Today I noticed I couldn't play videos from our conversation (both the ones I sent and the ones he sent). |author=everyoneelsethatlive |website=Reddit }}</ref>

If data is stored in a locked-in location from where it can not easily be [[:w:data portability|ported]] and is only accessible through specific software, the data will at most only be accessible for the lifespan of the one device it is stored on.

If an app is dependent on an online service, the unavailability or discontinuation of that service could make user data inaccessible, if the app is poorly designed to refuse starting if no connection to the service provider can be established.

Instances of software lock-in include:

* Some mobile browsers like Samsung Internet for Android (earlier known as "S Browser") lock saved pages away in the <code>/data/</code> directory, from where they can not be backed up or copied to other devices, except with root access, which is locked behind the bootloader by default, and unlocking that typically involves a full device erasure.<ref name=sadstate>[https://beepb00p.xyz/sad-infra.html ''The sad state of personal data and infrastructure'' - Karl Icoss, BeepB00p.xyz]</ref>
* In April 2019, software support for the "[[:wikipedia:software as a service|software as a service]]" Telekom Entertain 303 Media Receiver, a digital television apparatus, was deprecated. Since the operating system is software as a service, it stopped working as well, making recordings stored on the hard disk inaccessible. The USB port of the device could not be used for recording or file transfer, and the operating system could also not read USB sticks with existing media. It has no use beyond a 0.5A charger. Data on the device's hard disk was stored in a proprietary format.

The device was introduced in 2011, so people would lose up to eight years of recordings. But since data could not be moved anywhere else from the built-in 500 GB HDD of the device, people were forced to delete recordings anyway to be able to record new footage.<ref>{{cite web |last1=Schamberg |first1=Jörg |title=Telekom zieht 2019 beim alten "Entertain" den Stecker |url=https://www.onlinekosten.de/news/telekom-zieht-2019-beim-alten-entertain-den-stecker_214313.html |website=onlinekosten.de |access-date=3 October 2022 |archive-url=http://web.archive.org/web/20210412055921/https://www.onlinekosten.de/news/telekom-zieht-2019-beim-alten-entertain-den-stecker_214313.html |language=de-DE |archive-date=12 April 2021 |date=17 January 2019 |url-status=dead}}</ref>

== Overreliance on online services ==
While storing data both in an online service and locally reduces the risk of data loss compared to storing it only locally, people who have stored data into online services have repeatedly made the mistake of not retaining a local copy, which lead to them losing access to their data.<ref name=schneier-201409 />

For example, people uploaded [[:w:Home_movies|home videos]] on YouTube without locally retaining the original files. Due to the possibility of videos being removed and accounts being terminated in error, and the difficulty of reaching a YouTube employee for review, a local copy of such videos should be kept.<ref>[https://www.reddit.com/r/PartneredYoutube/comments/uo9oas/my_youtube_account_was_terminated_for_nudity_or/.compact ''My youtube account was terminated for "nudity or sexual content". Worried about losing thousands of hours of private/unlisted videos for our business.'' – /r/PartneredYouTube – Reddit (May 12th, 2022)]</ref><ref>[https://support.google.com/youtube/thread/127327365/my-channel-got-terminated-without-reason-no-strikes-no-warnings-i-worked-4-years-on-this?hl=en ''My channel got terminated without reason, (No strikes, no warnings) I worked 4 years on this .''  (September 23, 2021)] ("''I have old personal videos that I have not saved anywhere else in there saved as private and do not want to lose them.''")</ref><ref>[https://twitter.com/Quicksy7/status/1497226199080517635 Tweet from February 25th, 2022]: "''@TeamYoutube can you unban my old youtube account, it has alot of old video memories that i had not saved in my computer yet and all i would really want is to get them back[…]''"</ref><ref name=3things>[https://www.youtube.com/watch?v=vDJHHjnWAoc&t=01m02s ''3 Things I Wish I Knew when I First Started on YouTube'' (at 01m02s)] by Tim Schmoyer, Video Creators TV – honeymoon videos taken down due to copyrighted music in background.</ref>

Another example is that Google frequently locks user accounts and demands users to disclose their phone number to regain access. In Germany, it is mandatory since July 2017 to identify oneself to obtain a mobile phone number.<ref>{{cite web |last1=Pieruschka |first1=Von Marius |title=Prepaid-Karten: Ausweispflicht ab 01. Juli 2017 |url=https://www.4g.de/news/prepaid-karten-ausweispflicht-10764/ |website=4G.de – Das offizielle Infoportal zum Thema 4G, LTE, HSPA+ etc. |access-date=3 October 2022 |language=de-DE |date=5 August 2016}}</ref> Other countries have introduced similar laws over time.<ref name=SIM>{{cite web |url=https://www.privacyinternational.org/long-read/3018/timeline-sim-card-registration-laws |title=Timeline of SIM Card Registration Laws |website=Privacy International |date=2019-06-11 |access-date=2023-01-10 |language=en }}</ref> So Google holds accounts hostage until one provides personally identifiable information.<ref>[https://news.ycombinator.com/item?id=17944311 ''Tell HackerNews: Google requiring phone number to log into Chromebook'' – YCombinator – September 9th, 2018]</ref><ref>[https://www.reddit.com/r/privacy/comments/ks7cdt/google_is_forcing_me_to_enter_a_phone_number_to/ ''Google is forcing me to enter a phone number to login to my account'' – Reddit – /r/Privacy – January 7th, 2021]</ref><ref>[https://www.groovypost.com/unplugged/google-stop-asking-phone-number/ ''Google, Stop Asking Me for My Phone Number'' – Austin – GroovyPost – May 14th, 2012] ("''Despite skipping through the process multiple times, Google has continued to harass me with phone number requests. How many times will I have to login and skip it before Google gets the idea? Where is the opt-out button?''")</ref> Internet companies have disrespected users' privacy by using mobile phone numbers for commercial purposes in the past.<ref>{{cite web |url=https://thehackernews.com/2022/05/twitter-fined-150-million-for-misusing.html?m=1 |author=Ravie Lakshmanan |date=2022-05-26 |access-date=2023-01-29 |title=Twitter Fined $150 Million for Misusing Users' Data for Advertising Without Consent }}</ref>

An online platform might change its business model, resulting in a purge of prior data. For example, in 2022, Vimeo planned suspending accounts whose videos consumed excessive bandwidth.<ref>{{cite web |last1=Sato |first1=Mia |title=Vimeo is telling creators to suddenly pay thousands of dollars — or leave the platform |url=https://www.theverge.com/2022/3/15/22979126/vimeo-patreon-creators-price-increase |website=The Verge |access-date=18 June 2023 |date=15 March 2022}}</ref>

Among the largest data loss disasters on Internet social networking services occurred on MySpace. [[:w:Criticism_of_Myspace#Data_loss|The majority of audio tracks uploaded to the site were lost]], reportedly due to a maintenance error. The music tracks were listed but unplayable, with the earliest reports of tracks being unplayable dating back to December 2017.<ref>[https://www.reddit.com/r/Music/comments/7ij6br/myspace_music_profiles/.compact ''MySpace music profiles'' – Reddit post from December 9th, 2017]: "''I have music on a profile from when I was making music […] That is the only copy In Existence and would love to have it again for the memories''"</ref> Initially, the site's developers reported trying to solve the problem, presumably to delay an uproar, but later came to acknowledge that the data was permanently lost.<ref>{{cite web |last1=Brodkin |first1=Jon |title=Myspace apparently lost 12 years' worth of music, and almost no one noticed |url=https://arstechnica.com/information-technology/2019/03/myspace-apparently-lost-12-years-worth-of-music-and-almost-no-one-noticed/ |website=Ars Technica |access-date=24 September 2022 |language=en-us |date=18 March 2019}}</ref> The incident was dubbed a "datapocalypse", a [[:w:portmanteau|portmanteau]] from "data" and "[[:wikt:apocalypse|apocalypse]]".
Even after the web site spontaneously removed the user blogging feature along with existing user blogs without announcement in 2013, nearly five years earlier, some people were still not compelled enough to back up their data locally, resulting in them losing it.<ref>{{cite web |title=MySpace Punishes Its Few Remaining Friends By Vanishing Their Blogs |url=http://techcrunch.com/2013/06/12/bring-the-blogs-back/ |website=TechCrunch |access-date=24 September 2022 |date=12 June 2013}} ([http://archive.today/2014.03.16-194756/http://techcrunch.com/2013/06/12/bring-the-blogs-back/ Livefyre comment archive, 2014])</ref>

Cloud storage providers usually close long unused accounts to clear disk space for new users.<ref>{{cite web |last1=Novet |first1=Jordan |title=Dropbox shows how it manages costs by deleting inactive accounts |url=https://www.cnbc.com/2018/02/23/dropbox-shows-how-it-manages-costs-by-deleting-inactive-accounts.html |website=CNBC |access-date=3 October 2022 |language=en |date=23 February 2018}}</ref> Cloud storage is for short-term convenience, not archival. Exceptions are dedicated paid services with this stated purpose. However, due to lack of control, even those do not replace a local copy.<ref name=backblaze20200607>{{cite web |url=https://www.reddit.com/r/backblaze/comments/gykhsd/today_i_lost_12_tb_of_backblaze_protected_family/ |title= Today I Lost 12 TB of Backblaze "Protected" family Photos |website=Reddit (/r/BackBlaze) |date=2020-06-07 |archive-url=http://archive.today/2022.11.04-062318/https://www.reddit.com/r/backblaze/comments/gykhsd/today_i_lost_12_tb_of_backblaze_protected_family/ |archive-date=2022-11-04 |access-date=2023-12-03 }}</ref>

== Synchronization of bad data ==
A safe backup is independent from its source device. If a backup is automatically synchronized and there is no error detection mechanism, there is a risk of damaged data being synchronized.<ref name=backblaze20200607 />

== Loss of access credentials ==
Data in encrypted archive files or file systems or on a cloud service is at risk of loss if the access credential, commonly a password, is lost.
This is unlikely to happen over a short time span, but significantly likelier in absence in the long term.

As mentioned above, cloud storage providers purge long inactive accounts, meaning by the time one forgets the credentials to a long unused cloud account, it might not exist anymore.

== Loss and theft ==
Portable devices such as mobile phones that store data can be lost or stolen.

This risk is higher during trips, where one might, for example, leave a bag with personal belongings unattended in a crowded area.

The loss of data from such an occurance can be minimized by backing data up to a storage device left at the base (such as a hotel or rented appartment), and synchronized to a cloud storage service if the mobile data plan allows for it.

Although less likely, data could be lost to home burglary as well, especially when stored on the internal storage of expensive devices that are attractive to burglars due to their resale value. Data can only be protected from burglary by storing a copy in a separate location.<ref name=davdreamer>{{cite web |url=https://imgur.com/gallery/edTDPSV |date=2022-07-09 |author=davdreamer |website=Imgur |access-date=2023-01-10  |title=Stolen laptop in Westmeath Ireland, Please Help! |quote=the laptop has five years of photos as well as a book I had just finished writing! }}, "if I could hop in my time machine and back everything up I would."</ref>

== Natural disasters ==
In some locations of the world, people may have to be considerate about natural disasters. For example, a flood disaster could soak a basement, destroying all data storage except for optical discs. This can be prevented using water-tight bags or containers. A basement however is the least vulnerable to an earthquake due to being supported by the surrounding earth. An earthquake mainly targets the top of a house, which could be completely destroyed if the house collapses.

== References ==
<references />

[[Category:Backup]]
[[Category:Information technology]]