I've forwarded this to QA to see if they have an answer to this. It might be that we have to file a bug to get this fixed.

adobe has dropped support for the svg plugin back in 2009, so there's probably no way to get it working for the current browser versions again...

does the error message show up for every vector-graphic or only on special occasions?

See:

• bug 617448 - Browser fails to load correctly with svg.enabled set to false due to unqualified use of svg (remove svg.enabled pref)

This thread is about the same issue: https://support.mozilla.org/questions/914613

Regarding the "XML Parsing Error: not well-formed Location: <removed URL> Line Number 1, Column 1:", is this for SVG that you control and can fix, or is it for SVG that you don't have control over? If the former, the following document may help you fix the SVG:

https://jwatt.org/svg/authoring/

Thank you very much for the taking the time to reply, It's best if I answer them one by one.

madperson: It only displays the errors on that specific SVG file.

cor-el: The browser works fine, I just cannot disable the native SVG viewer, or chose which SVG viewer has priority.

djst: I had a look at that thread before I post but unfortunately I didn't solve the problem.

jwatt: Sadly it's not in my control to change the SVG, work related intranet.

This did used to work in the latest version of Firefox 3 and I don't know how the Adobe SVG viewer can somehow bypass these errors while the Firefox SVG viewer cannot?

It's not that Firefox can't bypass the errors, but rather that the developers chose to conform to the requirements of the relevant W3C specifications and treat errors as errors.

Unfortunately for you, the option to disable the built-in SVG support is gone for good. Besides that, Adobe's ASV is no longer supported and likely has unpatched security holes. Firefox 3.6 is also no longer supported and definitely has known, unpatched security holes, so you'd be strongly advised against trying to revert to 3.6.

If your company is unable or unwilling to fix the SVG on your intranet, then an alternative might be to create a Firefox add-on that can detect simple defects in SVG files and try to fix them so that they'll load. There are Firefox add-on devs out there that can be hired to do that sort of thing, and it may be more cost effective than fixing a large amount of SVG content. (I'm not sure where you would find such devs offhand, but maybe someone else can provide pointers on that.)

Got some more info from devs (via QA): The pref was removed in part because some of our UI uses SVG so it would not be sensible to disable it.

Further it looks like Adobe may not support this plugin anymore.

"so I think it's hypothetically possible that it _could_ work, if the plugin and Firefox were coded just right to allow an external plugin to register for handling SVG mimetypes (like PDF plugins register for handling PDF)... but I suspect the plugin might fight with us over who gets to handle SVG in our UI etc"

Our developer also wrote this: "[1:21pm] <dholbert>: juanb, it also sounds like the guy has an XML parsing error which is why he wants Adobe SVG 6.0... He probably just needs to fix his XML. We're probably being stricter than Adobe SVG was being"

Thanks ever so much jwatt & djst. It looks like the temporary solution for now is to use another browser to view the SVG files. Are XML parsing errors common enough to justify an investment in a plugin or would the general advise just use an alternative for now?

XML parsing errors are not common on the Web at all, since the vast majority of sites with SVG from the ASV era have long since been fixed up to work with native browser support. As for SVG on your intranet, well only you or others from your company can tell if it's common there, or if it's worth it to your company to invest in an add-on so that your staff can continue to view the SVG. If a different browser works for you, then it sounds like it probably is not.