ArcGIS freezes when opening most toolboxes

[AliceElliott]

I'm using ArcGIS 10.6.1 on Windows 10.

I work from home using a VPN to connect to my university's network. It's been nearly impossible to open any dialog boxes. For instance, I frequently use the Layer to KML tool, but the program hangs when I open it. The dialog box pops up, but then it never populates with any fields and I'm left with a white box. I have to shut down all of ArcMap and restart. No error messages or anything. I've left it running for a full half hour and it never resumes.

Here's what it looks like:

Even when I copy all the relevant files locally and do the same thing, it still freezes.

Thanks in advance for any help you can provide.