Follow the below steps to resolve:
Step One: Unpost Entries
Ensure a Backup has been taken of the Ledger.
Go to Data Entry.
Select Unpost All Entries.
Select OK to both pop up messages.
Step Two: Sync Depreciation
From the top panel menu select Assets.
Select Assets.
Click the second button.
Integrated Calc / Depn Sync.
In the next window, click the same button to Save Calculations.
Step Three: Repost Entries
Go to Data Entry.
Select Post Entries.
Ensure the Period Range is correct. By default the To criteria will need to be adjusted.
Click Post, then Yes.
Close the window.
Check that the error has cleared.