Hi Kamen, my analysis of your problem was not complete: In fact, the problem is a bit different from what I wrote: If you pass persistent objects as argument to a transaction and you delete that object within the transaction, serializing the transaction arguments to the transaction log result in the warning that you have seen. The datastore emits a warning because the object is no longer in existence after the transaction has been executed. Upon restore, this will not be a problem since no log entry is written, but the warning is annoying nevertheless. My suggestion, using "destroy-object" from your transaction, does not help, because you still have the persistent object in the argument list to the transaction function. A proper workaround is to pass only the object ID in the argument list to the transaction (this is how delete-object works). Another workaround is to remove the warning from the datastore. Maybe I will do that in the future, but I have to think about it some more. My remark about deleting blob files still holds, though. -Hans