As has been pointed out below, when people have to “guess” extremely relevant information such as your operating system and the Shotcut version you are using, you aren’t likely to get the help you might want (you still haven’t provided this either, so that deadline can’t be too close eh 
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With that being said, I’m going to make some assumptions here, and the first is that you are a Windows user. Follow the instructions in this post carefully:
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If that doesn’t work then create a new user profile and install fresh on that for testing purposes and report back.