- Uninstall ClearContext
- Upgrade to 2010 x86 (CC supports 32bit only at the time of this post)
- Reinstall ClearContext
In some cases, upgrading to 2010 with ClearContext installed results in the following error when opening email:
The form region "ClearContext.RelatedView" cannot be opened. An add-in returned an error while loading the form region storage. The return type must be a path to the form region storage file or the contents of the form region storage.
This issue is likely caused by the presence of the add-in component Microsoft Office 2007 Primary Interop Assemblies. Remove it via Windows Control Panel to eliminate the issue.
The following error may also occur at startup:
A form region cannot be opened. The form region manifest contains invalid XML.
Resolve by disabling show add-in user interface errors. See this post for more detail.
Option 2 - An alternate fix for both errors removes MessageContext from messages, tasks and appointments.
- Follow directions here to remove registry pointers to MessageContext
- Open File > Options > Advanced, page down to the Developers section and de-select "Show add-in user interface errors"
You may need to re-run Option 2 if the errors return after a future ClearContext upgrade.

