Lexmark C2335/CS531/CS632/CS639 printer platform — 55.1
Lexmark 55.1 means the printer cannot read the attached USB flash drive. The guidance here is specific to C2335/CS531/CS632/CS639 printer platform and the USB storage operation.
Error meaning
The printer cannot read the attached USB flash drive.
This interpretation is tied to the reviewed family/platform and subsystem. Do not reuse the code by itself on another printer family.
Applies to
C2335/CS531/CS632/CS639 printer platform
- C2335
- CS531
- CS632
- CS639
Common formatting
These are lookup/formatting aliases for this reviewed condition, not separate pages.
- 55.1
What usually causes it
- The printer cannot read the attached USB flash drive. The print engine can otherwise be healthy; the failure concerns the removable storage device, its format, or the USB-host path.
- The exact condition recorded for this code is: The printer cannot read the attached USB flash drive.
- Remove the drive safely, confirm it can be read on a computer, and try a modest-size supported flash drive with a file type the printer normally accepts. Avoid using a hub or unusual adapter during the test.
What to try
Check the condition this code actually names
Remove the drive, verify it is supported/readable elsewhere, and try a supported drive.
Isolate the affected part of the workflow
Remove the drive safely, confirm it can be read on a computer, and try a modest-size supported flash drive with a file type the printer normally accepts. Avoid using a hub or unusual adapter during the test.
Run a controlled confirmation test
Reconnect the known-good drive directly and wait for the printer to recognize it before selecting a file. If one drive works and another does not, keep the diagnosis with the media rather than the printer.
After each corrective action
Retry the original operation that produced 55.1. If it works, stop there rather than moving into unrelated troubleshooting.
If the code returns
If 55.1 occurs with multiple known-readable supported drives, record whether the USB port powers the devices and whether any other USB-host message appears.
When service may be needed
Do not open the printer to repair the USB port. Repeated failure with supported media should be escalated as a USB-host or controller issue.
Continue with guided troubleshooting
If the printer still is not working after the reviewed checks, carry this verified error context into the guided troubleshooter.
Related information
Verified source
Official four-model User’s Guide (2026 edition) contains the printer error-code section and safety cautions.