Your Only RAR Backup Is Corrupt After a USB Format: Can You Save Any Files?
A 750 MB file size means bytes were saved, not that the RAR contains a complete, readable archive. You may still extract some files if the archive has readable internal members, but there is no method that can recreate compressed data that was never copied correctly or has since been overwritten.
In this only-backup RAR case, the owner packed wanted PC files into a RAR on a USB drive before reinstalling Windows, copied the RAR back to the computer, and then formatted the USB. Both WinRAR and 7-Zip failed to extract it, WinRAR's repair attempt had already failed, and Recuva did not locate a usable earlier copy. Recovering even a subset of the files would help.
Try to Salvage Content Without Altering the Original
- Step 1
Keep the existing 750 MB RAR unchanged and make a duplicate on a healthy drive. Stop writing to the formatted USB until the chance of an earlier copy has been assessed.
- Step 2
On the duplicate, try WinRAR's Keep broken files option during extraction to a new folder, then inspect any output that survives. The WinRAR feature documentation says partially extractable damaged content can sometimes be retained. This is not guaranteed, particularly if no archive entries can be read.
- Step 3
If no usable members extract, look for an intact earlier RAR or original backup files on the formatted USB, other disks, or cloud copies. Do not repeat the same unsuccessful repair on your only archive.
When Does USB Data Recovery Help?
If the pendrive is still recognized and stays stable, Recoverit USB Data Recovery can search the formatted USB for a surviving earlier archive or original files, saving anything found to a different drive. That is recovery of an older copy, not a repair of the current corrupted RAR. Success depends on whether formatting and subsequent writes left the relevant sectors intact.
Recovery limit: If both the remaining archive and any older storage copies lack essential compressed bytes, neither a repair option nor another scan can recreate those missing contents.