If you are using Sage 50 Missing Invoice and your invoices have disappeared, there are a few things you can do to try and fix the issue. First, check to see if the invoices are in the Recycle Bin. If they are, you can restore them from there. If not, you can try running the data recovery tool that comes with Sage 50. This tool will scan your hard drive for any missing or corrupted data files. If it finds any, it will attempt to repair them.