We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

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.

Unable to install add-on on my mac

  • 1 reply
  • 6 have this problem
  • 1 view
  • Last reply by TonyE

lcarper
lcarper
more options

I am unable to install any add-on to my Mac. The message I receive is:

Firefox could not install the file at

https://addons.mozilla.org/en-US/firefox/downloads/latest/4076/addon-4076-latest.xpi?src=external-AT_tooldl

because: Unexpected installation error Review the Error Console log for more details. -203

I am unable to install any add-on to my Mac. The message I receive is: Firefox could not install the file at https://addons.mozilla.org/en-US/firefox/downloads/latest/4076/addon-4076-latest.xpi?src=external-AT_tooldl because: Unexpected installation error Review the Error Console log for more details. -203

All Replies (1)

TonyE
TonyE
  • Moderator
more options

See unexpected installation error -203 when installing add-ons