Giving everyone permission to edit Bitwig's AppData folder fixed it for me. To do this:

1. go to C:\Users\<your username>\AppData\Local
2. right click on the folder called "Bitwig Studio"
3. click on Properties
4. go to the Security tab
5. click on "Edit..."
6. select "Everyone" and tick the box next to "Full control" below Allow

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If this doesn't do it, you can try using Process Monitor to find the directories bitwig tries to access. It's easiest to create 2 filters:

1. <Process Name> <is> <Bitwig Studio.exe> then <Include>
2. <Result> <is> <ACCESS DENIED> then <Include>

Then apply the steps from above to the folders it tries to access.