How to Fix OctoPrint Issues – Keeps Printer On, Disconnecting & More

Many people experience issues with OctoPrint such as the software keeping their screen on, a constant disconnecting or pausing of the connection, or OctoPrint that keeps starting in safe mode.

This article will take you through a series of fixes that have worked for other users with the same issues.

How to Fix OctoPrint That Keeps Ender 3 Screen/Printer on

The main reason OctoPrint keeps the Ender 3 screen on is through a phenomenon called back powering. This happens because the USB cable that connects the Raspberry Pi to the 3D printer has a live 5V terminal that transfers power.

If the printer is turned off, the 5V terminal will still power the printer’s board leaving it on. In some cases, it can even perform some basic functions, leading you to believe the printer is still on.

However, this is not ideal, since it can have adverse effects on the printer’s electronics.

Here’s how to fix OctoPrint that keeps the Ender 3 screen on:

1. Power on and shut down the printer and the Pi properly.
2. Cover the 5V terminal with tape
3. Cut The 5V wire
4. 3D print a pin isolator for the 5V terminal

1. Power On and Shutdown the Pi Properly

Shutting down your 3D printer and Raspberry Pi properly after printing helps you avoid back powering your printer’s board. Also, when you’re turning them on, you have to follow the proper power-up procedure.

When starting up OctoPrint, make sure your printer is turned on before you connect it to the Pi via USB. Also, when you’re shutting down the printer, make sure you power down and disconnect the Pi board first.

After doing this, you can power down your printer safely.

2. Cover The 5V Terminal with Tape

To stop the Raspberry Pi from transferring power to your printer, you can block the USB’s 5V terminal with tape. This is very helpful in scenarios where you want to turn off the printer but leave the OctoPrint server running.

The electrical tape will cover the terminal preventing it from making contact and powering the printer. There is a very helpful guide on the OctoPrint forum that shows how you can do this.

To do this, turn the USB A side of the cable over so its pins are facing upwards. The last pin from the left is the 5V terminal.

Cut off a sliver of electrical tape that’s just wide enough to cover the 5V terminal. Using a pair of tweezers, gently position the tape over the terminal.

The tape should cover the entire length of the 5V terminal to the back for it to be effective. Once it’s in place, it will block any power transfer.

A user even reported that doing this helped solve their connection issues. However, be careful not to let the tape block any of the other terminals, as they are very important.

You can see an example in the picture below.

3. Cut the 5V Wire

Cutting the 5V wire is the most effective if not a somewhat messy method of stopping USB power transfer.

Using a box cutter, carefully cut open the USB cable. Look for the red 5V power wire and cut it. Make sure you don’t cut any of the other wires or it won’t work.

Cover the ends of the cut wire with electric tape then place the wire back in the sheath and cover the sheath with electrical tape. It should work fine after this.

4. 3D Print a Pin Isolator for the 5V Terminal

Another method of covering the 5V terminal rather than using tape is to 3D print a USB-A Male Plug Pin Isolator from Thingiverse. After printing it, just slide it over your USB head and it will insulate the 3D printer’s positive terminal.

OctoPrint Keeps Disconnecting/Crashing or Going Offline – How to Fix

1. Try another USB cable
2. Check for a loose USB port on your 3D printer
3. Move electronics to a different circuit
4. Check for electromagnetic interference
5. Restart the Wi-Fi router
6. Put electrical tape over the 5V line

1. Try Another USB Cable

A simple fix for when your OctoPrint software keeps disconnecting or going offline is to try another USB cable. You want to get one that’s good quality, as well as preferably short and protected.

I’d recommend going for something like the Amazon Basics or Anker Cable from Amazon.

2. Check for a Loose USB Port on your 3D Printer

One user who was experiencing OctoPrint that kept on disconnecting found that the problem originated from his USB port on the 3D printer being too loose. He was running the latest version of OctoPrint on a Raspberry Pi 3B and getting these connection issues on his CR-10 Mini.

The first thing he tried was to change out the cord, but it ended up disconnecting again.

He fixed the loose USB port without opening the 3D printer by plugging in the cable and twisting it so it was at a sharp angle with a little bit of force on the connector, then taped it to the control box. He also taped the excess cord to the table to make sure it doesn’t move.

3. Move Electronics to a Different Circuit

There might be an issue with your electronics being on the same circuit. One user found that when he turned on a fan that was on the same circuit, it caused issues with OctoPrint disconnecting and going offline.

Once he figured out what was going on, he moved things to their own circuit and it’s been running fine since.

Another user noticed that their OctoPrint would crash when they turned on a light that their Pi and Ender 3 was connected to. Changing the circuit so it was clean fixed their issue.

4. Check for Electromagnetic Interference

Some people have reported issues happening due to electromagnetic interference in the area. One user had an issue where the cable between his Raspberry Pi and 3D printer board ran straight past his gas log fire heater.

He learned that when he turns his heater on while printing, it disconnected his OctoPrint which meant that G-Code stopped being sent to the 3D printer. There are similar interferences that can happen with other electronics so try moving these away to see if it fixes the issue.

Other objects like a microwave, fridge, washing machine, vacuum cleaner, or even fluorescent lights can cause interference.

You can get an error in your OctoPrint logs like “usb_serial_generic_read_bulk_callback – urb stopped: -32” in dmesg.

5. Restart the Wi-Fi Router

A simple restarting of your Wi-Fi router can help address this issue. A user said he was having this issue a few months back with 3 Raspberry Pi’s connected to 3 3D printers. He said that all of the Pi’s needed to be periodically rebooted to reconnect to the Wi-Fi.

At the initial stages, he was using an Arris AB66700AC Modem/Router with a Comcast Cable, then ended up adding a TP Link AC1350 as his new Wi-Fi access point, while keeping the Arris as a modem and DHCP server.

After making this change, he hasn’t had a connection issue, so it could have been to do with the original Arris device.

6. Put Electrical Tape Over the 5V Line

Similar to the fix that keeps the Ender 3 screen on, putting electrical tape over the 5V line can help fix this issue. The reason for this is that you can experience backpowering issues where the 3D printer tries to draw power from their 5V power from devices connected via USB.

You can use something like the 3Pcs Electrical Tape from Amazon.

For a Raspberry Pi, it can cause undervoltage issues which can negatively affect stability and overall performance. This has affected specific 3D printers such as the Ender 3, Ender 5 Pro, CR-6 SE, Geeetech Aluminum i3 Pro and more.

How to Fix OctoPrint That Keeps Starting in Safe Mode

When OctoPrint keeps starting in safe mode, it means that it can’t start up properly without it. It’s not triggered by a bad shutdown of OctoPrint. You’ll want to check out your log files and upload it to the OctoPrint forum to get some assistance.

One user said he skimmed the log file and found that it had a complaint about the filament manager plugin. He ended up removing it from his OctoPrint instances and it helped solve the issue.

When you select the option to restart OctoPrint in safe mode, it should only affect the next restart of OctoPrint. Other than that, OctoPrint can go into safe mode due to a plugin problem, where you then have to disable the plugin it mentions.