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Parsing Error: undefined entity, Line Number 744, Column 15.

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  • Last reply by kiernan1

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Firefox won't load. I'm getting a Parsing Error: undefined entity, Line Number 744, Column 15. I have uninstalled Firefox and reinstalled but it still won't work. How do I fix this?

Firefox won't load. I'm getting a Parsing Error: undefined entity, Line Number 744, Column 15. I have uninstalled Firefox and reinstalled but it still won't work. How do I fix this?

Chosen solution

Did you try a clean reinstall and delete the Firefox program folder ?


You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

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Chosen Solution

Did you try a clean reinstall and delete the Firefox program folder ?


You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

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I did a clean reinstall, but did not delete the old folder. Thank you, I have done that now and reinstalled and it worked.