Picture scan crash

[birchler1]

Application Identifier: com.hardcoded-software.dupeguru
Application Version: 4.0.3
Mac OS X Version: Version 10.12.2 (Build 16C67)

Traceback (most recent call last):
File "build/dupeGuru.app/Contents/Resources/py/shelve.py", line 111, in getitem
KeyError: 'path:/Users/birchler1/Desktop/Paperless Library.paperless/Thumbnails/2013/11/19/Thumbnail-84D95310-D16B-4AFD-881F-7CC280013274.png'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "build/dupeGuru.app/Contents/Resources/py/cocoa/inter.py", line 259, in pulse
File "build/dupeGuru.app/Contents/Resources/py/hscommon/gui/progress_window.py", line 101, in pulse
File "build/dupeGuru.app/Contents/Resources/py/core/app.py", line 323, in _job_error
File "build/dupeGuru.app/Contents/Resources/py/hscommon/jobprogress/performer.py", line 43, in _async_run
File "build/dupeGuru.app/Contents/Resources/py/core/app.py", line 780, in do
File "build/dupeGuru.app/Contents/Resources/py/core/scanner.py", line 137, in get_dupe_groups
File "build/dupeGuru.app/Contents/Resources/py/core/pe/scanner.py", line 31, in _getmatches
File "build/dupeGuru.app/Contents/Resources/py/core/pe/matchblock.py", line 167, in getmatches
File "build/dupeGuru.app/Contents/Resources/py/core/pe/matchblock.py", line 65, in prepare_pictures
File "build/dupeGuru.app/Contents/Resources/py/core/pe/cache_shelve.py", line 121, in purge_outdated
File "build/dupeGuru.app/Contents/Resources/py/shelve.py", line 113, in getitem
KeyError: b'path:/Users/birchler1/Desktop/Paperless Library.paperless/Thumbnails/2013/11/19/Thumbnail-84D95310-D16B-4AFD-881F-7CC280013274.png'

[ghost]

Duplicate to #402