The below steps should resolve the error:
Ensure that all users are out of all HandiSoft programs.
One user will open HandiLedger only. If they use any other programs to open HandiLedger they need to ensure that they close these programs.
Select the relevant entity. This will display in bold at the top of the window.
Select Tools from the menu bar, and click Rebuild Database files.
Select Entity Details, User reports and Formats, and Standard reports & formats.
Select Rebuild, and agree to the prompts. Let this complete.
Once completed, other users can re-enter the programs and the issue should be resolved.