Firefox extension not compatible with browser (Flock, Mozilla, Seamonkey…) version: What to do?

You really want to install this Firefox extension but you can’t? Because it’s not compatible with your browser (screen shot)? Or you have upgraded your browser and some of your favourite add-ons got disabled? Happens a lot with more exotic extensions, or if you’re using a minority browser like Seamonkey, (the old) Mozilla, or (the brand new) Flock. However, you do not need to despair:

Extensions (add-ons) not compatible with browser version after upgrade

More often than not, the extension is compatible, but the developer hasn’t tested it yet, or at least not updated the version information in the .xpi install file. But that one, you can do for yourself.

How to change browser version information for a .xpi file?

Firefox extension install files are in fact just zip files with another extension. So here’s how to proceed (on Windows, but probably analogously for other systems):

  1. Right-click the link to the .xpi install file and “Save As”
  2. Rename the xpi file to .zip
  3. Extract the zip file
  4. Edit install.rdf with your favourite text editor

Typically, you’ll either need to:

Update the em:maxVersion element in the em:targetApplication description for your browser (change e.g. 0.8 to 1 in the example):

<!-- Flock -->
<em:targetApplication>
  <Description>
    <em:id>{a463f10c-3994-11da-9945-000d60ca027b}</em:id>
    <em:minVersion>0.4</em:minVersion>
    <em:maxVersion>0.8</em:maxVersion>
  </Description>
</em:targetApplication>

Or insert the missing “em:targetApplication” browser description if your browser is not listed:

  1. Copy the lines above from<em:targetApplication> to </em:targetApplication>
  2. Paste them after the last </em:targetApplication> in the file
  3. Change “Flock” in the example to your browser name and the long (“guid“) em.id element to one of these:
    Firefox {ec8030f7-c20a-464f-9b0e-13a3a9e97384}
    Mozilla Suite {86c18b42-e466-45a9-ae7a-9b95ba6f5640}
    SeaMonkey {92650c4d-4b8e-4d2a-b7eb-24ecf4f6b63a}
    Netscape Browser {3db10fab-e461-4c80-8b97-957ad5f8ea47}
    Flock Browser {a463f10c-3994-11da-9945-000d60ca027b}
  4. Update the the em:maxVersion number again to at least your current browser version

Install a modified extension by just drag and drop from your hard-diskThat’s it! All you have to do now is zip up those files again with the changed install.rdf, rename the .zip file to .xpi and just drag and drop the .xpi file in a browser window…

And what if the extension does make my browser crash?

If your browser crashes before you can even uninstall (via Tools… Add-ons), have a look the extensions folder for your user account. That should be something like:

C:\Documents and Settings\[your-username]\Application Data\[Flock/Browser,Mozilla/Firefox]\Profiles\[somehash.default]\extensions

Find out the folder for the misbehaving extension (by checking name, modified date or contents), and simply delete it. Your browser will start up again normally next time.

4 Responses to “Firefox extension not compatible with browser (Flock, Mozilla, Seamonkey…) version: What to do?”

  1. Firefox 3 Beta2 « That guy next door Says:

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  2. Chris Says:

    Or just force it to install with Nightly Tester Tools (google it). Much easier.

  3. Damien Says:

    Thanks for this tip. I’d done this before but couldn’t remember which file needed to be edited to change the maxversion.

    thanks again,
    Damien Moria

  4. Jos Says:

    I tried this with an add-on (an experimental one – I don’t know if that fact is relevant) but two strange things happened. Firstly, turning the XPI into a ZIP didn’t allow it to open. Secondly, while the XPI could be opened itself in a text editor, em: does not appear in the text, making the rest of the steps impossible. (This is a long shot – could it be that I’m using 7-Zip instead of WinZip to open archives? 7-Zip cannot open it as a ZIP, or even when its XPI status is restored for that matter.)