Hi , briefly in 2012 I zipped a wallet.dat and renamed it to .jpg ,
the drive had been formatted to NTFS.
the recovery software has brought the .jpg home but it is not able to return to .zip
Just to make sure, you did rename the file to
<>.zip, right?
Because in case you did, the chances are high that your file is corrupted.
Which recovery software has been used? And do you still have an untouched copy/image of your old drive?
If you are simply formatting a drive most of the data will stay intact. The probability of a small .zip file to be corrupted are relatively small. It might have been the recovery software which didn't recover the file as it should (maybe uses different techniques for .jpg).
Another image of the drive could be useful for analysis with other (better) tools.
If you do not have such an image left, you probably have to follow NeuroticFish's advise and try out a zip-recovery tool.