This is a description of a workaround for Canon shooters who have problems tethering to Capture One Pro 7.0 in combination with OS X Lion and Mountain Lion.
Status
Currently Canon has not yet released the needed software (SDK or Software Development Kit) to support both Lion (up to 10.7.5) and Mountain Lion (10.8.x). However, Canon's latest EOS Utility 2.12.x does support Lion and Mountain Lion for tethering. As soon as Canon releases the new SDK and Phase One builds it into CO7, this workaround becomes obsolete.
Solution/workaround
What I propose and explain in this post is how you get the best from Canon and put it into Capture One Pro 7. In plain English: copy the SDK in EOS Utility and place it into Capture One Pro 7.
Prerequisites
You need administrative privileges on your system (be an admin, not regular user).
Process
The process involves the following steps
1) download and install EOS Utility 2.12.0 (or later)
2) get the SDK from EOS Utility
3) replace the SDK in Capture One Pro 7.0 with the newer version from EOS Utility
The steps described below may seem complicated and overwhelming at first sight, but it is really easy to do.
Step 1
Go to your localized Canon site and download and install EOS Utility 2.12.0 Updater (or later). If you do not have already EOS Utility installed on your computer, you only need to insert your Canon EOS Digital Solution disk in your CD/DVD drive for detection and the updater will install the software.
Step 2
In Finder, go to the EOS Utility program icon (Applications/Canon Utilities/EOS Utility). As you might know, this a folder with subfolders.
Right-click on the application (do not start it up), select "Show Package Contents" (SPC).
The path to the SDK folder is:
EOS Utility (SPC) > Contents > Frameworks > EDSDK.framework > Versions > A
Copy the entire contents of folder A to a temporary location (Desktop for example). This should be 4 items.
Step 3
In Finder look up Capture One in the Applications folder.
Tip
Before we proceed, you might want to rename it, for example into "Capture One - Canon". This allows you to install a second and unaltered version of Capture One 7 in the Applications folder as a backup and fall back scenario. This also prevents you from accidentally overwriting the modified version when installing an update.
As with EOS Utility, do not start it but right-click in Finder on Capture One and select "Show Package Contents" (SPC). Now we drill into it until we find the SDK folder:
Capture One (SPC) > Contents > MacOS > CaptureCoreServer (SPC) > Contents > Frameworks < CaptureCore > Canon > ED-SDK > EDSDK.framework > Versions > A
Copy the the 4 items from the A folder of EOS Utility to this Capture One A folder to replace 4 items with the same name.
Close the Finder window and start Capture One, connect your camera and shoot tethered.
Good luck!