The Thunderbird Command Error 12, or BAD Command Argument Error 12, often occurs when Mozilla Thunderbird tries to connect to the email server via IMAP but fails because the email server rejects the “ID” command. This guide explains how to fix the Command Error 12 and troubleshoot the Thunderbird IMAP connection problem.
What does the Thunderbird Command Argument Error 12 Mean?
The error message pops up when the user tries to connect to the server while opening Thunderbird, downloading messages, or sending emails.
It appears in the Activity Manager or Connection Status bar at the bottom.
In this scenario, when Mozilla Thunderbird sends an introduction command to the server to set up a connection.
The introduction command sent by Mozilla Thunderbird looks like:
ID ("name" "Thunderbird" "version" "115" "os" "Windows")However, certain email servers, and in most common cases, Exchange/Outlook reject the argument or the ID command as they may not support IMAP extensions.
And send back the Command Error 12 Thunderbird.
Fixes to Thunderbird BAD Command Argument Error 12
If you are trying to access your email account in Thunderbird and cannot access it, and keep getting the Thunderbird Command Error 12 over and over again, it can be frustrating.
However, do not worry, even if the error appears, your email data is still safe on the server, and it is not any kind of security threat.
Fix 1: Disable the mail.server.default.send_client_info Error
Thunderbird enables you to manually stop sending the ID command and make the connection directly so that Thunderbird command argument error 12 does not pop up.
- Open Mozilla Thunderbird.
- Click on the Settings (Gear) icon at the bottom left.
- Search for Config Editor in the Find in Settings search bar.
- Open Config Editor.
- Press Ctrl+F and search for
mail.server.default.send_client_info. - Click on the swap button to turn off the settings, and the status displays False.
- Restart the Thunderbird application.
Fix 2: Remove the Thunderbird Command Error 12 Using the Repair Folder
The user may also get a BAD Command Argument Error 12 when Thunderbird tries to access data that might have been deleted from the mail server.
Thus, the server cannot process the request and returns Command Error 12.
You can simply use the native Repair Folder option in Thunderbird to fix the error and restart Thunderbird.
General Troubleshooting Steps to Get Rid of Thunderbird Command 12 Error
These general troubleshooting steps can help resolve the Thunderbird command error quickly.
- Empty the Trash and Spam folders
- Launch Thunderbird in Safe Mode
- Upgrade to the latest version of Thunderbird
- Disable antivirus and proxy to seamlessly connect Thunderbird to the server without error.
FAQs
Q1: Why does Command Error 12 mostly appear with Exchange?
Although you can connect Thunderbird to Exchange via IMAP, Exchange does not support all IMAP-based commands, and thus, the error pops up. Also, Thunderbird is a third-party app for the Exchange-based email client. To resolve this, you can also migrate Thunderbird to Outlook.
Q2: Does the “Unrecognized Command ID” error affect email access in Thunderbird?
No, Thunderbird as an email client displays all the conversations better served and application. So if the command is rejected, the error pops up; however, nothing else is affected.
Q3: Can I clear the cache on Thunderbird to fix the error 12?
Yes, it can help in some cases, but not always. You can go to Settings >> Disk Space and check the Clear out cache option and then restart Thunderbird.
Tired of Common Errors like BAD Command Arguments in Thunderbird?
If you want to switch or upgrade to a better, more business-oriented email client without any data loss in the simplest way. You can use the Thunderbird Migration Tool or get in touch with migration experts using the Live Chat option.
