You can't use the ICD with the PIC running at greater than 40Mhz.
There's no real reason other than MCS+ won't let you.

But, you can increase the divider so the the core runs at a lower freq.
_CPUDIV_OSC3_PLL4_1L will give 24mhz.

Then change to DEFINE OSC 24.

Also, the ICD is not compatible with standard USB routines.
It will likely drop the connection to the PC because it's not servicing fast enough. (Unless using USB_ASM_Service.pbp)
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