A few days ago, our company file suffered some corruption after its server shut down unexpectedly while many users were still logged in. We ran it through the Optimization Assistant and it came out clean. We decided to go ahead with using the repaired file instead of restoring a backup.

However, we have been mysteriously losing orders since then. Today, only 17 of the 33 orders inputted yesterday morning are still in the system. We are not receiving any errors and everything else works fine; simply, the orders disappear without a trace, sometimes within hours of inputting them.

As it has been several days, restoring from a backup is now very impractical due to the amount of data loss. Is there any way to fix this?

You need to submit this file to your MYOB support team and ask them to check it/fix it. You should schedule this with them first, to minimise down-time.