[ul][li]Please type /dopusdata into the location field in Opus, and push return, so it takes you to your Opus configuration folder.
[/li]
[li]Zip up the Collections directory below there.
[/li]
[li]Open the same configuration folder in Explorer.
[/li]
[li]Exit Opus completely, by right-clicking its taskbar icon and choosing Exit Directory Opus. (Just closing all windows is not enough, unless Opus has been configured not to run in the background.)
[/li]
[li]In the Explorer window, delete the Collections folder.
[/li]
[li]Start Opus again. Does it still crash?[/li][/ul]
If it no longer crashes, please send the zip containing the old Collections folder to GPSoftware (if it's easier, sent it to me via a private message, and I'll pass it on).
On the other hand, if it does still crash, see if a mini-dump file is created. Please send the mini-dump(s) in a zip along with a screenshot of the crash message (or just the screenshot if there are no mini-dumps).