Step to reproduce issue:
1. Start up iClone 7.81
2. Load an 'Avatar' (custom or default template, anything would work)
3. Select your character in the veiwport
4. Press [N] to open 'Edit Motion Layer' & click the FK mode
5. Pick a bone (from the 'Edit Motion Layer' window) and modify one or two spine bones
6. Save as "test.iProject"
7. Open "test.iProject" from 'File > Open Project' (without closing the software)
8. Press [N] to open 'Edit Motion Layer' (doing the same thing over again)
9. Pick a bone (FK mode on the 'Edit Motion Layer' window) and modify one or two spine bones

Actual Result: iClone Crashes! The error message as attached appears before it's down.

Can it be fixed? I've experienced this so often since 7.8 and it has not been fixed during 7.81 update.