The log file says:
2020-12-04 22:00:00,806+0100 INFO texworks - starting: MiKTeX TeXworks 0.6.5 (MiKTeX 20.11)
2020-12-04 22:01:19,920+0100 FATAL texworks.core - A required file system path could not be retrieved.
2020-12-04 22:01:19,920+0100 FATAL texworks.core - Data: nfolder="5", hr="-2147024891"
2020-12-04 22:01:19,920+0100 FATAL texworks.core - Source: Libraries\MiKTeX\Core\Utils\win\winUtils.cpp:72
2020-12-04 22:01:19,947+0100 FATAL texworks - MiKTeX exception: A required file system path could not be retrieved. 2020-12-04 22:01:19,947+0100 FATAL texworks - Info: nfolder="5", hr="-2147024891"
2020-12-04 22:01:19,947+0100 FATAL texworks - Source: Libraries\MiKTeX\Core\Utils\win\winUtils.cpp
2020-12-04 22:01:19,947+0100 FATAL texworks - Line: 72
2020-12-04 22:01:26,410+0100 INFO texworks - starting: MiKTeX TeXworks 0.6.5 (MiKTeX 20.11)
2020-12-04 22:01:36,846+0100 FATAL texworks.core - A required file system path could not be retrieved.
2020-12-04 22:01:36,846+0100 FATAL texworks.core - Data: nfolder="5", hr="-2147024891"
2020-12-04 22:01:36,846+0100 FATAL texworks.core - Source: Libraries\MiKTeX\Core\Utils\win\winUtils.cpp:72
2020-12-04 22:01:36,871+0100 FATAL texworks - MiKTeX exception: A required file system path could not be retrieved.
2020-12-04 22:01:36,871+0100 FATAL texworks - Info: nfolder="5", hr="-2147024891"
2020-12-04 22:01:36,871+0100 FATAL texworks - Source: Libraries\MiKTeX\Core\Utils\win\winUtils.cpp
2020-12-04 22:01:36,871+0100 FATAL texworks - Line: 72
I have ALL newesst Updates. Anybody an Idea?