[slowsmile]

@najgori...The problem you're having is that the "tidy.dll" library could not be loaded when you ran the CustomCleanerPlus plugin on your system. This library file is located on your system at:

C:\Users\Lapis\AppData\Local\sigil-ebook\sigil\plugins\CustomCleanerPlus\tidylib\win6 4\tidy.dll

I've also just downloaded and run the CustomCleanerPlus plugin from MR and I ran it (using Bundled Python) without any problems on a test epub using Sigil(v1.2) on my own Windows 10 system.

The only thing I can suggest for now is that your "tidy.dll" library file might have been corrupted on initial plugin download. Perhaps best if you remove the original CustomCleanerPlus plugin from Sigil and then try downloading and installing the plugin from MR again and retry.