Failed to launch worker process

[klonuo]

I just updated to 0.8.31 and now I can't add ebooks to library

Launching from terminal throws this error when I try to add ebook:

Exception in thread Thread-9:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 552, in __bootstrap_inner
self.run()
File "/usr/lib/calibre/calibre/utils/ipc/server.py", line 221, in run
worker = self.launch_worker()
File "/usr/lib/calibre/calibre/utils/ipc/server.py", line 139, in launch_worker
raise CriticalError('Failed to launch worker process:\n'+cw)
CriticalError: Failed to launch worker process:
Traceback (most recent call last):
File "/usr/lib/calibre/calibre/utils/ipc/server.py", line 149, in do_launch
conn = self.listener.accept()
File "/usr/lib/python2.7/multiprocessing/connection.py", line 145, in accept
c = self._listener.accept()
File "/usr/lib/python2.7/multiprocessing/connection.py", line 267, in accept
s, self._last_accepted = self._socket.accept()
File "/usr/lib/python2.7/socket.py", line 202, in accept
sock, addr = self._sock.accept()
error: [Errno 4] Interrupted system call

[chaley]

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