Hi Waqar Ahmad,

The extension for the backup company file is .qbb. You can find it in the QBBBackup Temp (.tmp) folder, which is automatically created when you back up your files. 

On the other hand, the .qbw you mentioned is the file extension for a working file in QuickBooks Desktop for Windows.

You can check out the article about the list of file extensions for more details.

If there's anything that you need help with, feel free to click on Reply below.