SpinRite 6 "MBR Followed by EFI" Error

I got the following response from SpinRite support:

The current version of SpinRite, v6.0, was finished in 2004 before the era of GPT partitions, so it is completely unaware of that style of hard drive formatting. Consequently, SpinRite v6.0 can handle MBR-formatted drives up to 2.2 terabytes, but not GPT-formatted drives of ANY size.

GPT (GUID partition tables) are only required for drives larger than 2.2 terabytes because MBR format partition tables are limited by their 32-bit fields for specifying the partition size and starting location. 32-bits == 4,294967,296 and if you have that many 512-byte sectors, you wind up with 2,199,023,255,552 bytes ... or 2.2 terabytes.

Though this doesn't help you now, support for GPT-format partitions is one of the major features of the next release (v6.1) of SpinRite -- which all existing v6.0 owners will be able to upgrade to at no cost.

However, there is no time line on the next version of SpinRite.

Thank you for your cooperation, time and patience.

So, it does not look like the current version of SpinRite supports modern, large capacity drives.