I’m sorry to hear about the loss of your data!
Unfortunately, I’m not aware of any cause of this issue, short of harddisk
corruption whereby the SlickRun MagicWord library file
(%userprofile%\appdata\roaming\slickrun\SlickRun.srl) is corrupted or deleted by
hardware failure. Currently, that library is only backed up when you upgrade
(see the Backup subfolder).
Is there any chance you have any “interesting” software installed (e.g. 3rd
party security software, or any software like OneDrive or DropBox that attempts
to roam or backup your files to the cloud)?
I would recommend using the Windows “Scan for Errors” tool:
You might also consider creating a batch file to periodically backup your
SlickRun library file somewhere (e.g. copy it to a dropbox or onedrive sync’d
folder, for instance).
I’d also suggest upgrading to the very latest version of SlickRun (v4.3.1)
just to ensure that you’re on the latest.
all the best,