Kory: Thanks for the tips. We are in the process of moving to 10.7.x in the next few weeks, I'll see what happens with the tool then. Unfortunately, Dan's suggestion to backup the data so that ESRI can test is understandable, but very difficult to do. The particular behavior of the problem suggests that it's a condition getting unknowingly setup at the user (client) session. The actual data being read resides on an actively used MS-SQL 2016 server with multiple users and making backup copies before each run of this particular tool (we use it a lot) is pretty difficult. Secondly, it's essentially HIPAA-level confidential data and I'd have to go through the tedious process of anonymizing the data in order to send to ESRI. And that process itself could change the nature of any data-related problem causes. The tool runs in the ArcMap context and is only reading data. We use it to read data from 'plain' (non-spatial) SQL database and compare it to the corresponding features in a spatial enterprise geodatabase. It then generates a report in Excel, highlighting the values that need to be checked or where spatial features are missing altogether. (and conversely where spatial features do exist but should not) One of my concerns is that it's using the python module 'pymssql' to access the non-spatial database, and I'm getting the impression recently that I should probably be using 'pyodbc' instead. pyodbc seems to be getting more attention recently and may be a more solid python interface to a SQL server. Another noticeable feature of this problem is that it only started appearing on the user workstations that were upgraded from Windows 7 to Windows 10. (while remaining with ArcMap 10.4.1) But that doesn't tell me what or where to start looking for a problem. I'll be testing ArcMap 10.7.x soon. And I am considering inserting intensive logging output in the python code so that I may be able to at least narrow down where the problem is occurring. :George
... View more