[KevinH]

Please try the off the record approach. If that works we at least have a safety net.

We can then revert and try to track down exactly where the damn cache files are going on Windows so that they are properly cleared.

According to latest qtbase code it should go here:

extracted from qtbase source in github from src/corelib/io/qstandardpaths_win.cpp

QString QStandardPaths::writableLocation(StandardLocation type)
{
    QString result;
    switch (type) {
    case CacheLocation:
        // Although Microsoft has a Cache key it is a pointer to IE's cache, not a cache
        // location for everyone.  Most applications seem to be using a
        // cache directory located in their AppData directory
        result = sHGetKnownFolderPath(writableSpecialFolderId(AppLocalDataLocation));
        if (!result.isEmpty()) {
            appendTestMode(result);
            appendOrganizationAndApp(result);
            result += "/cache"_L1;
        }
        break;

But it somehow ends up in roaming and seemingly without the final "cache" folder?

Does this folder even exist?

C:\Users\<??????>\AppData\Roaming\sigil-ebook\sigil\cache\