My document and sub-document names in tree view keep disappearing. I have re-entered them three times (tedious) using F2 / rename. It lasts for a couple days and then crashes again. Here is a photo.

Even the backup document that I saved on a different drive has the document names missing, so the bug must be in the software somewhere, not the *.mio file.
Please help. I don't want to re-enter 40+ names again!
Thanks,
Aisha