MobileRead Forums - View Single Post - Cannot Access CBR or CBZ Files Because of File Being Used by Another Process

calibreian · 06-20-2025, 06:37 PM

Hi all,

I'm having an error trying to open CBR files via Calibre. I've seen this question asked in one or two other places on the web and I asked on Reddit but got no solution. EPUB and PDFs are working, but not CBR or CBZ. Here's the error when trying to access via Firefox over network:

Traceback (most recent call last): File "calibre\srv\books.py", line 127, in job_done Permission Error: [WinError 32] The process cannot access the file because it is being used by another process: '\\?\C:\Users\Username\AppData\Local\calibre-cache\srvb\s\stkhp40k' -> '\\?\C:\Users\Username\AppData\Local\calibre-cache\srvb\f\0e3331f92ac8026a750dbf4fd0280b385c200 74a'

My Calibre library is not on the network, it's in C:\Users\Username\*, I've tried it in a few other places as well, the same message pops up. I've used ProcessManager and Powertoys File Locksmith and neither say the folders/files are being accessed by anything else. I've allowed Calibre-Parallel.exe through the firewall and have no alternate antivirus software or OneDrive.

Also, from what I know of how Calibre works, when a CBR is accessed, it creates files in the appdata cache folders that contain the entire CBR as JPG files. Though every time I try to open a CBR, including books that have already been opened, it recreates those JPG files in a new cache folder each time, which seems counterintuitive, as some CBRs are 200+ MB, which quickly makes the cache folder 1+ GB. This functionality seems incorrect, meaning I must have something wrong that coincides with the error I'm seeing. There are also two Calibre Worker Processes running in the task manager, though if I kill either one, it doesn't even passed the loading screen of the book - not sure if this is related.

Any help would be greatly appreciated! I'd love my books to be accessible.

06-20-2025, 06:37 PM	#1
calibreian Member Posts: 11 Karma: 10 Join Date: Jun 2025 Device: Android Tablet	Cannot Access CBR or CBZ Files Because of File Being Used by Another Process Hi all, I'm having an error trying to open CBR files via Calibre. I've seen this question asked in one or two other places on the web and I asked on Reddit but got no solution. EPUB and PDFs are working, but not CBR or CBZ. Here's the error when trying to access via Firefox over network: Traceback (most recent call last): File "calibre\srv\books.py", line 127, in job_done Permission Error: [WinError 32] The process cannot access the file because it is being used by another process: '\\?\C:\Users\Username\AppData\Local\calibre-cache\srvb\s\stkhp40k' -> '\\?\C:\Users\Username\AppData\Local\calibre-cache\srvb\f\0e3331f92ac8026a750dbf4fd0280b385c200 74a' My Calibre library is not on the network, it's in C:\Users\Username\*, I've tried it in a few other places as well, the same message pops up. I've used ProcessManager and Powertoys File Locksmith and neither say the folders/files are being accessed by anything else. I've allowed Calibre-Parallel.exe through the firewall and have no alternate antivirus software or OneDrive. Also, from what I know of how Calibre works, when a CBR is accessed, it creates files in the appdata cache folders that contain the entire CBR as JPG files. Though every time I try to open a CBR, including books that have already been opened, it recreates those JPG files in a new cache folder each time, which seems counterintuitive, as some CBRs are 200+ MB, which quickly makes the cache folder 1+ GB. This functionality seems incorrect, meaning I must have something wrong that coincides with the error I'm seeing. There are also two Calibre Worker Processes running in the task manager, though if I kill either one, it doesn't even passed the loading screen of the book - not sure if this is related. Any help would be greatly appreciated! I'd love my books to be accessible.