Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More
This thread was archived. Please ask a new question if you need help.
Archived

Won't load, error cord 0xc000012f

Thunderbird Troubleshooting
LisR replied
LisR
LisR

All of a sudden, I cannot open Thunderbird. Worked this morning, not anymore. 

I get an error code4 0xc000012f.  What can I do?
All of a sudden, I cannot open Thunderbird. Worked this morning, not anymore. I get an error code4 0xc000012f. What can I do?

All Replies (2)

Matt
Matt
  • Top 25 Contributor

Have you restarted (rebooted) your device? If not do so.

LisR
LisR Mwenye swali

Thanks, but yes, first thing I tried. Actually, I wound up rebooting twice. I followed the advice for another Firefox problem thinking it may help Thunderbird as well, so I had to reboot for that too. Still no good. I was eager to NOT lose my saved emails so I hesitated uninstalling Thunderbird and then reinstalling. Instead, I decided to try 'repairing' the app by simply downloading a new copy without uninstalling the current one first. It went through the normal paces and ran the installer wizard. All of a sudden, the program opened and all is well... everything saved is still there. I don't have 2 Thunderbird installations, as far as I can tell, but it apparently worked to download a 'fresh' copy.... whatever, it worked! So, issue RESOLVED! Thank you so much!