This sounds like two separate problems. First:
> My neighbor is using your ThumbsPlus V10. She swears she hasn't changed any settings but all of her thumbnails are gone.
This could happen if she made a new thumbnail database, if she moved her images to a different drive or folder or renamed the folder(s) (not using TP), or if a program other than TP was used to give her drive a different volume label (so that TP would no longer recognize it as one for which it has thumbnails in its database).
Or, maybe the thumbnails are still there but the display filter (funnel icon above the thumbnail listing) is set to a file pattern or selection that doesn't match anything.
> I told ThumbsPlus to scan her Tree and Disk. In the bottom right pane it shows it is scanning, but it jumps from 33%, 66%, then 100% and then there is a yellow !.
It looks like TP stumbled over an incompatible or excessively large zip-file there.
If your neighbor does not need the ability to scan image files that are stored inside zip files, I'd recommend turning off "Options | Preferences | Disks & Folders | Display ZIP files as folders". Then they will be ignored and this error should no longer occur.
If these suggestions don't help, don't hesitate to let me know. In that case it would be helpful if you mention:
- The number of thumbnail records and the total file size shown under Database | Statistics
- The Database Path shown under Help | System Info.