If you are installing from the blue disc, you shouldn't have any problems.
But remember to right-click the install program and "Run As Administrator".
If you are installing from an older Black and White disc, there are a few extra steps to follow.
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Re: Latest PIC support - PIC 18FxxQ20 family
Hi, Roger
Acetronics2 Today, 18:56May be you'd better ask to Charles here : https://support.melabs.com/forum/picbasic-pro-compiler-3-0-and-later/pbp3-picbasic-pro-3-0/page46
but don't rejoice too quickly...
Alain