I had a 3.01 database where resource R1 had no Base Unit of Measure specified. I then upgraded to 3.7A and found that: a) I cannot create Job Journal lines for R1 because the Resource UOM does not exist (Resource=R1, UOM=’’) b) I cannot create a Resource UOM with UOM=’’ c) I cannot change R1’s Base UOM to some non-blank value (“You cannot change Base UOM because there are ledger entries for this resource”) This means that no Job Journal lines can be created now for R1, which is a serious problem. a) and b) make sense, but c) does not - specifying a Base UOM should only affect new entries, so it does not matter if there are posted entries - is it a bug? Can you see any problems arising if I change BaseUOM.OnValidate so that it doesn’t check for Ledger Entries? Thanks, Alastair Incidentally, the Resource UOM table did not exist in 3.01. [I moved the topic from End-User Questions]