Hi Ted,
No bother at all... and gladly share my experiences from an active user perspective, but not much of a techie to resolve computer and communication issues.
I also still run Cumulus1 full time on an old Windows 8 PC, and have run it on my newer Windows 10 PC without any issue.
However CumulusMX does so much more so run more than one version
using WiFiLogger and WLL.For your Cumulus1 have you checked the Diags files, and is there anything there that might indicate the issue?
The same for your CumulusMX have you checked MXdiags files? There is much more diagnostics in MXdiags. I would gladly look at the MXdiags if you were to zip and attach or PM. But likely more support on Cumulus forum as Simon indicated.
If the older data is in your monthly log and dayfile files but not displaying I wonder if there is perhaps some corrupt data. Does it all show correctly in the CMX local dashboard Data Log tab > Monthly logs and Dayfile? Does it all look correct in the \data\Aug21log.txt and dayfile.txt when you open with Notepad++?
Enjoy,
Paul