My Mac Pro shows a grey screen, an Apple logo, a horizontal status bar and a rotating circle, but it does not fully boot up. I tried the NVRAM reset but that does not seem to have worked. Any other ideas?
Try a SMC reset first:
Resetting the SMC (System Management Controller) on Intel-based Macs:
Resetting your Mac's PRAM and NVRAM:
Firmware updates for Intel Macs:
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