Update: We released OmniFocus 2.13.1 on April 1st, 2016, which contains a fix for this issue.
After the release of OmniFocus 2.13, some customers let us know that they were unable to add a new Inbox item, or view the Inbox, without encountering a hang that leaves the app inoperable. This can also manifest as a hang on launch, or a hang in the Past section of Forecast.
OmniFocus 2.13.1 contains a fix for this issue. If you’re unable to update to this version for whatever reason, you may be able to work around the problem.
This hang is caused by a large number of completed items in your Inbox (it could also appear in any project, but so far we have seen it mostly with Inbox). The workaround is to remove those items.
Archiving in OmniFocus for Mac
If you are syncing to a Mac, you can use the Archive feature in OmniFocus for Mac to clear out those older completed items. That process is covered in the OmniFocus for Mac Documentation on our website.
If you need help with this procedure, please contact our support team using the contact information below—we’re happy to help!