RegSvr32 Error Message when PC Boots

When my wife's Win 10 (64 bit Pro) PC boots, it get a "RegSvr32" Message with a simple "X" in the box. There is no specificity as to what the error (if any) is -- just the simple popup box with an X. When the box is closed there is no apparent problem running any of her programs.

The PC is virus free and no registry errors are detected using (e.g.) CCleaner.

I just ran Windows 10 SFC /scannow and ZERO issues were detected.

Any ideas on how to eliminate the popup?

Tanks,

Louis

The popup was being created by a small application file located in a "roaming" folder. When disabled the popup stopped. I have removed the offending file and the problem has gone away -- permanently. This issue is solved.