So this can happen for a number of reasons (see below) and we have a pretty good Kb article (KB175775) that discuses the cause and possible ways to fix it
This behavior may occur for one or more of the following reasons: A corrupted browser choice setting may cause Windows to misinterpret which browser is set as the default browser on your computer. Settings were changed after a software installation that cause webpages not to work correctly. A previously installed browser or add-on may be interfering with other software on your computer. Registry key were changed or became corrupted
This behavior may occur for one or more of the following reasons:
The Kb article gives 4 possible resolutions:
as well as various advanced troubleshooting tips and additional support options.
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