[KevinH]

The real error in that output log is:

Could not load library: C:\Users\Juerg\AppData\Local\sigil-ebook\sigil\plugins\CustomCleanerPlus\tidylib\win6 4\tidy.dll


So my guess is the tidy.dll file inside the plugin could not be found, or if found, can not be loaded because it is in some way incompatible.

Things to explore:

- could your python be 32 bit and the tidy.dll be 64 bit, or visa-versa? Same for Sigil?

- could the provided tidy.dll be linked with some other dll that does not exist on the target system but does exist on slowsmile's system as it may have been built there?

I am thinking of something like tidy.dll might needs a specific lib c++ to exist on the target system?

You could try testing the plugin on a another system that was never used to build the tidy.dll just to see if it works there.