[kbaerwald]

After updating to Windows 10 (1903) and update to Calibre Release: 3.45.2 [12 Jul, 2019] I have reproducable errors after exiting the calibre viewer and calibre editor:

calibre, version 3.45.0
ERROR: Unhandled exception: <b>SystemError</b>:error return without exception set

calibre 3.45 [64bit] embedded-python: True is64bit: True
Windows-10-10.0.18362-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.18362')
Python 2.7.15+
Windows: ('10', '10.0.18362', 'SP0', u'Multiprocessor Free')
Interface language: en_GB
Successfully initialized third party plugins: ... (hidden)
Traceback (most recent call last):
File "site-packages\calibre\gui2\viewer\main.py", line 379, in closeEvent
File "site-packages\calibre\gui2\viewer\main.py", line 366, in shutdown
File "site-packages\calibre\gui2\viewer\main.py", line 392, in save_state
File "site-packages\calibre\utils\config.py", line 448, in __setitem__
File "site-packages\calibre\utils\config.py", line 411, in commit
File "site-packages\calibre\utils\config.py", line 432, in to_raw
File "site-packages\calibre\utils\config_base.py", line 86, in json_dumps
File "json\__init__.py", line 251, in dumps
File "json\encoder.py", line 209, in encode
File "json\encoder.py", line 434, in _iterencode
File "json\encoder.py", line 408, in _iterencode_dict
File "json\encoder.py", line 313, in _iterencode_list
File "json\encoder.py", line 39, in encode_basestring
SystemError: error return without exception set

Any idea? [edit:has been reported, sorry for double info]

Klaus