[dae]

I get this error message when starting up. Cannot add new books, other parts of program just shut down instantly. I have tried reinstalling calibre 3 times, both 32 and 64 bit.

calibre, version 4.2.0
ERROR: Startup error: There was an error during calibre startup. Parts of calibre may not function. Click Show details to learn more.

Traceback (most recent call last):
File "site-packages\calibre\gui2\main.py", line 292, in initialize_db_stage2
File "site-packages\calibre\gui2\main.py", line 236, in start_gui
File "site-packages\calibre\gui2\ui.py", line 434, in initialize
File "site-packages\calibre\gui2\init.py", line 781, in save_layout_state
File "site-packages\calibre\gui2\library\views.py", line 636, in save_state
File "site-packages\calibre\gui2\library\views.py", line 630, in write_state
File "site-packages\calibre\db\cache.py", line 62, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 616, in set_pref
File "site-packages\calibre\db\backend.py", line 134, in set
File "site-packages\calibre\db\backend.py", line 131, in __setitem__
IOError: IOError: disk I/O error

I've run chkdsk, and there is no error. I think this may be a Windows update issue. I have not been able to rollback latest windows updates (they immediately reinstall themselves).

What to do?