Hi @CheSusumY,

This could happen when there are transactions that cannot be taken for Revaluation calculation. 

For an example, you have have an Inventory Part where Inventory Valuation Method is “Standard Cost”. You receive some quantities for the Purchase Order of this part. After that, you change the Inventory Valuation Method to  “Weighted Average” and Supplier Invoice Consideration to “Transaction Based”. And then you post a Manual Supplier Invoice for that order receipt (but the price and invoice amount differ)

As a result, a transaction revaluation event is triggered. But, this event finds the above transaction quite problematic, because the transaction has been created under standard cost but the part is now weighted average, therefore in the Transaction Revaluation Events window it will indicate that there were some problematic postings that came across during revaluation. Hence, the Revaluation Not Possible is ticked.