eBook viewer slow to open when recent disk resource unavailable
In Calibre 2.80 on Windows x64:
1. Configure Calibre eBook Viewer is set to remember recently opened files.
2. Browse to a UNC network path or a removable device that contains an eBook that Calibre can open.
3. Open the file in the Calibre eBook viewer.
4. Close the file.
5. In some way, disable the UNC network path so that it is not available, or remove the removable device.
6. Attempt to open an eBook on a local drive using the Calibre eBook Viewer, and notice the file opens very slowly.
7. Close the eBook viewer.
8. Repeat step 6 to show that caching the book doesn't help.
9. Close the eBook viewer.
10. Open the eBook Viewer with no file using the Start Menu shortcut, and it is still slow, showing it's not an issue with the eBook being opened.
10. Restore access to the UNC network path or insert the removable device, and repeat step 6, and now access time is normal.
This can be worked around by either clearing the list of recently opened files, or configuring the viewer not to remember recent files.