It appears a Windows update from last week is breaking older Excel-based reports. This is NOT a bug in our software, and it is not something we have any control to fix. The issue is a missing/changed/updated/broken Excel driver (and it appears to be an older, JET/MDAC 3.6 driver). We have been unable to determine if the driver has been removed or simply changed/broken.
We have had three different customers report this issue so far.
If you Google search "windows update tuesday october 10 2017, excel", you will find some discussions on applications that read Excel data files breaking due to the update.
This Microsoft forum discussion acknowledges the problem:
This SAP article acknowledges the problem:
We imagine Microsoft will fix this issue in a future update. In the meantime, if you want to fix this issue, you'll probably have to upgrade the driver the report uses and/or reconfigure the data connection with new driver (in Crystal Reports, Database, Set Location, then UPDATE to a New connection).
Some users have rolled back update KB4041676 on Windows 10 or KB4041681 on Windows 7 to fix the issue. This is obviously not a permanent solution, though.