I backed up a database:
BACKUP DATABASE MyDatabase
TO DISK = \'MyDatabase.bak\'
WITH INIT --overwrite existing
And then tried to restore it
I had the same issue... although I do not know why my database experienced this problem as my drive was not full... It's like it got corrupted or something. I tried all of the above none of them fully worked, I especially thought the suggestion to stop the service and deleting the mdf and ldf files would work... but it still froze up on restore?
I ended up resolving this by deleting the files as mentioned but instead of trying to restore the DB again I copied over fresh .mdf and .ldf files and Attached these using the Front End Attachment wizard. Relief, it worked!!
It took FOREVER to copy over the new files as I am using a Virtual Machine... so copying and pasting using the clipboard took like an hour itself so I would only recommend this as a last attempt.