If you have received an error similar to this from the AssetAccountant™ interface:
"Cannot XXXXXXX an asset with an effective date prior to unreversed events"
This is usually a setup problem in that you are attempting to make changes, for example reassessments, to data that is applicable prior to your opening balance date.
Which is the date you nominated for AA to start calculating from the previous closing balances in your previous system (Excel, Xero, ERP, old desktop software like MYOB, etc.)
Depending on how long ago your data was imported, it is always best to start with the correct data in AA.
Bad data in = bad data out, unfortunately.
So it is best to delete the asset(s) and start over.
If you have many assets affected, you could either archive your flawed register OR rollback your previously imported data and start again.
But you may have already journaled multiple times making this messy.
Assuming this isn't viable, you have 2 options:
1. Reassess your affected assets for the beginning of the next period.
2. If you absolutely must change the fundamental details of your assets prior to the opening balance date, manually reverse the opening balance for each asset, then manually apply the required changes, then manually reapply the opening balance back for each asset.
This would need to be done on an asset-by-asset basis.