Cannot switch profile to recover from backup

My windows 8 laptop got blue screen error & crashed,didnot sync with Ankiweb but got the Anki data recovery from hard disk.lappy recovered with format,copied previous data & I installed Anki which loaded with same previous user profile & 2 decks cards loaded…after doing cards,I tried to close it but it showed sync error message,backup message keep on running continuously & tools>database showed corrupted file…I tried to switch profile to load backup but the same sync error message,backup message comes up keep on running & not loading profile …any solution Please???Anki is very important to me Please help me to solve my problem

Problem solved with this method
I experienced this problem, as well–I wasn’t able to use the suggested Switch Profile option suggested above because of the error nir1a explained with a screenshot in Post #11 above: after clicking Switch Profile, Anki displays the error message “Your collection file appears to be corrupt. …” and then displays a “Backing Up…” progress popup that never ends. At that point, Anki is frozen.

I think the corruption occurred because I was backing up the Anki2 folder using Google Drive, which I just learned is an unsupported practice that’s know to cause issues. I was using my laptop offline a lot, and there may have been some sudden disconnections, which would affect both Anki and Google Drive sync.

Here’s how I solved it without having to revert to an older Anki version. Note: I had automatic backups enabled, so no local data was lost, but even if you don’t have a local backup, this process will also enable you to “Switch Profile” and sync from the web:

  1. Close Anki (Force Quit/End Task if necessary).
  2. Rename the profile folder in the Anki2 folder (find that by reading the Anki manual: Managing Files/File Locations) by appending “_OLD” (don’t delete; it contains automatic backups and media files. FYI, the default profile name is User 1.
  3. Open Anki. Dismiss prompts about empty collections.
  4. Restore a backup that you would find in the backups folder in the “_OLD” profile folder you just renamed, or restore from another .colpkg file, or sync all changes from AnkiWeb to the new profile (please research how to do that if it’s your only option–it’s beyond this post’s scope)