If you are using QuickBooks 2010 and above, there is another utility function to restore a current backup file to an earlier version.  For example, you have your company file in QuickBooks 2013 and have made a backup file.  But then you run into problems and you want to restore the 2013 backup file to QuickBooks 2012 and work on it.
You can’t restore the 2013 backup file using regular File > Open or Restore Company > Restore a backup copy function, because of how different versions of QuickBooks use different method of compressing backup files.

You have to do the following instead:

1.    In Earlier Version of QuickBooks (QuickBooks 2012 in the above example), go to Main Menu > File > Utilities > Restores Backup for Earlier QuickBooks Version to open its dialog box:

 

QB Restoring backup to Earlier Version of QuickBooks 1


2.    In the “Select the backup file from you want to restore”, enter the backup filename from QuickBooks 2013 (,QBB), or click the ellipsis (…) button to open “Open Backup Copy” dialog box and choose your backup file in your computer. Click Open.

3.    In the “Where do you want to save the restored file?”, enter the file name where you want to restore your file (,QBW), or click the ellipsis (…) button to open “Save Company File” dialog box.
Select the folder you want and name your restored company file in QuickBooks 2012. Click Save.

4.    You will be brought back to “Restore Your Company File” dialog box in Step 1 with the “Backup filename” and “Restored filename” fields filled in. Click OK.

5.    Once the program is successful in restoring your file, a message will appear:

 

QB Restoring backup to Earlier Version of QuickBooks 2


6.    Click OK and now you have restored the QuickBooks 2013 backup file into QuickBooks 2012 working file.