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Firefox won't start up

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  • Last reply by Kiki

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When I try to start Firefox, the following dialog box appears:

XUL Runner Error: Platform version 128.0.3 not compatible with minVersion >= 128.0 maxVersion <= 128.0

Clicking the OK button closes the attempt to start Firefox.

Do I need to reinstall the latest version? If I do, will all my info be saved? Jan

When I try to start Firefox, the following dialog box appears: XUL Runner Error: Platform version 128.0.3 not compatible with minVersion >= 128.0 maxVersion <= 128.0 Clicking the OK button closes the attempt to start Firefox. Do I need to reinstall the latest version? If I do, will all my info be saved? Jan

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Hi janhsvec,

This is a known issue caused by a corrupted installation after a failed update. The workaround is to uninstall and then re-install Firefox to fix this issue while our team is working on a more permanent fix. You shouldn't lose any data if you download the full installer from our official source.

Sorry about the inconvenience!