Cannot add any books to Calibre

[nirvandal09]

I've been using Calibre for many years without issue. A couple of weeks ago, I decided to throw Calibre Portable on a WD Passport external HDD. It's been working fine and I've been able to do everything until today. I tried adding an EPUB to my library and got this error:

calibre, version 2.59.0
ERROR: Cannot add books: Failed to add any books, click "Show details" for more information.

Failed to start worker process
Traceback (most recent call last):
File "site-packages\calibre\utils\ipc\pool.py", line 197, in start_worker
File "site-packages\calibre\utils\ipc\pool.py", line 185, in create_worker
File "site-packages\calibre\utils\ipc\pool.py", line 71, in start_worker
File "site-packages\calibre\utils\ipc\simple_worker.py", line 160, in start_pipe_worker
File "subprocess.py", line 710, in __init__
File "subprocess.py", line 958, in _execute_child
WindowsError: [Error 2] The system cannot find the file specified


I thought maybe it was an issue with the file or format I was trying, so I tried to add a PDF file and got the same issue. I was able to add files earlier today so I tried adding one of the files I had done a couple hours before. Same error. I tried disabling the metadata READER plugin for PDF and EPUB, still got the same issue. I ran the check library util and didn't get back any errors. The only thing that changed between now and the last time I added books, is I did try to run a large job to convert ~300 books to MOBI. About halfway through the job, I needed to leave and take my laptop with me, so I cancelled the jobs and closed out of Calibre.

Any help would be greatly appreciated.

Thanks!

[kovidgoyal]

That error indicates the calibre-parallel.exe file is missing from the calibre program folder. Maybe your antivirus quarantined it or the installation got corrupted in some other fashion. Re-install should fix it.

[nirvandal09]

That worked. Thanks!