Canon Printer Error E55 — Unsupported USB Device

What Does This Error Mean?

Error E55 appears when an unsupported device — such as an incompatible USB flash drive, USB hub, or peripheral — is plugged into the printer's USB host port. The printer only supports specific USB memory sticks for direct photo printing. Removing the unsupported device or replacing it with a compatible USB stick clears the error.

Affected Models

Canon PIXMA MG5720
Canon PIXMA MG5750
Canon PIXMA MG6820
Canon PIXMA TS9120
Canon PIXMA TR8520

Common Causes

A USB flash drive in a format the printer cannot read (exFAT, NTFS, or HFS+) was plugged in
A USB hub was connected to the printer's USB host port — printers do not support hubs
A USB hard drive or other high-power USB device was connected
A USB device with a non-standard controller chip is incompatible with the printer's USB host
The USB flash drive contains no recognised image files in the root folder

How to Fix It

Remove any USB device connected to the printer's front or side USB host port.

This is the port used for direct photo printing from a USB stick — not the USB port used to connect to a computer.
Turn the printer off, wait 30 seconds, and turn it back on.

This clears the error state caused by the unsupported device.
If you want to print photos directly from USB, use a FAT32-formatted USB flash drive.

Canon printers only support FAT32-formatted drives. Drives over 32 GB may need to be formatted as FAT32 using a computer.
Make sure the USB flash drive contains JPEG image files in the root folder.

Some printers will not read images stored in subfolders. Move photos to the root directory of the drive.
Avoid connecting USB hubs or USB hard drives to the printer's USB host port.

Only standard USB flash drives are supported for direct printing.

When to Call a Professional

E55 is a compatibility issue, not a hardware failure. No professional service is needed. If after removing the USB device the error persists, a full power cycle will clear it.

Frequently Asked Questions

What USB flash drives are compatible with Canon printers?

Canon printers support FAT32-formatted USB drives containing standard JPEG photos. Drives up to 128 GB formatted as FAT32 generally work. Avoid exFAT or NTFS formats — these are not supported.

Can I connect a USB hub to print from multiple drives?

No — Canon printers do not support USB hubs on the host port. You can only connect one USB device at a time. Swap drives manually between print jobs.

Is E55 the same as E54?

No — E54 is a USB communication error between the printer and a computer. E55 is specifically about an unsupported device plugged into the printer's own USB host port for direct printing. They are different error types with different causes and fixes.