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

How do I open an XUL file with the Remote XUL Manager addon? (MAC)

  • 5 replies
  • 1 has this problem
  • Last reply by cor-el

more options

I'm kind of a newbie, and have never seen an .xul file in my life. My grandmother has an .xul file that she's trying to open, but it won't work. Stupidly, I updated the OS from Snow Leopard (10.6) to El Capitan (10.11) and I'm not sure if that was the source of the problem. I looked everywhere for a solution, or some way to open it, but all evidence pointed to Mozilla Firefox. When I double-click the .xul file, it opens in Firefox and the error message reads:

Remote XUL

This page uses an unsupported technology that is no longer available by default in Firefox.

   Please contact the website owners to inform them of this problem.

Okay..? I tried installing the Remote XUL File Manager to help me with this. I tried to add the domain by copy and pasting the url of the file, which is "file:///Volumes/ANCESTRY/HannahLane1940census%20-%20Copy%20-%20Copy.xul". But I get:

XML Parsing Error: undefined entity Location: file:///Volumes/ANCESTRY/HannahLane1940census%20-%20Copy%20-%20Copy.xul Line Number 586, Column 7: <checkbox id="trackingProtection"


When I open it on her Windows laptop, the file extension changes to .htm, which I assume is because Macs don't support .htm or .html file extensions anymore. When I try to open that in any browser, I get:

%brandDTD; %globalPreferencesDTD; %preferencesDTD; %privacyDTD; %tabsDTD; %searchDTD; %syncBrandDTD; %syncDTD; %securityDTD; %sanitizeDTD; %mainDTD; %aboutHomeDTD; %contentDTD; %applicationsDTD; %advancedDTD; ]>

I have tried installing previous versions of Firefox, (I have 44) but to no avail. I have also tried running it in safe mode, and completely restarting and refreshing the Firefox application itself. Can anyone help me? I honestly feel guilty for updating to El Capitan, and I hope there's a way to use Remote XUL Manager so I can open this file.

All Replies (5)

more options

Did you check the content of this file by prefixing the link with the view-source: protocol?

  • view-source:file:///Volumes/ANCESTRY/HannahLane1940census%20-%20Copy%20-%20Copy.xul

Were did she get this file?

Does Ancestry end such files?

more options

I'm not sure where she got it.

I entered that into firefox and got a bunch of stuff, I don't know what any of it means.

more options

That is the source code of the about:preferences page: view-source:about:preferences You can remove that file as there is no need to do anything with it.

more options

So, does that mean there's no way to see this file? Do you know if it was because I upgraded the OS?

more options

There is not need to do anything with this file as this file is supposed to bring up the about:preferences page and is of no use. It probably got saved by accident like doing a "Save Page As" while the about:preferences was visible (had focus).

If you want to replicate this then open the about:preferences in a tab and save that page and compare the files.