Markkk Man, that is terrifying, especially with VMware backups on the line. First rule: Don't panic, and absolutely do not initialize, format, or "Clean" anything if Windows prompts you to. Your data is almost certainly still intact; Windows is just completely misinterpreting the partition table right now.
A "GPT Protective Partition" usually means the new PC's operating system or the USB bridge chip inside your external enclosure is failing to read the GPT routing headers properly.
Since you absolutely cannot wipe this drive, here is how I would narrow this down without risking your data:
1. The "Sanity Checks" (Hardware & Host)
Try the original PC first: If you still have access to the first computer, plug it back in immediately. If it mounts fine there, the issue is 100% with the second PC's environment (drivers, USB controllers, or legacy BIOS/UEFI settings), not a corrupted SSD.
Bypass the enclosure: If this is a DIY external SSD (an NVMe or SATA drive inside a third-party case), those cheap bridge chips are notorious for misreporting drive geometry to different motherboard controllers. If you have a desktop, pull the SSD out and plug it directly into an internal M.2 or SATA slot.
Motherboard Ports Only: Drop any USB hubs. Plug it straight into the rear I/O panel (directly on the motherboard) to rule out power drops.
2. Check what's actually going on via DiskPart
Since you mentioned DiskPart sees the size, let's see if it's just the OS being stubborn. Open CMD as Admin and run:
diskpart > select disk X > list partition
If Windows treats it as a "Protective Partition," it usually locks you out of Disk Management entirely (you won't even be able to right-click to change drive letters). If list partition shows your backup partition but lists it as "Type: Unknown" or "Protective" instead of "Primary", the partition table itself got slightly scrambled during the swap.
3. The Linux/Mac Rescue (Highly Recommended)
Windows is incredibly rigid. If a partition header is even one bit off, Windows throws its hands up and calls it "Protective" to prevent accidental overwrites.
- The trick: Linux and macOS have way more resilient partition parsing logic. Make a quick Live Ubuntu USB, boot into it, and plug your drive in.
- In 90% of these cases, Linux will bypass the Windows lock, read the NTFS/exFAT file system perfectly, and let you copy those massive VMware backups safely to another drive before you do a clean wipe.
What NOT to do
Whatever you do, do not run the clean command in DiskPart. A lot of old forum threads suggest this to "reset" the drive, but it will completely blow away your partition headers. While the data is technically recoverable after a clean, it makes getting those VM backups back a massive headache.
Try moving it back to the original PC first if you can, or try the Linux live boot trick. Let us know how it goes!
