WIERD -- GPT NTFS 3TB HDD issue

I used diskpart to set id from 'EFI System' partition to 'basic data' partition, works perfectly !

Using this ref:

GUID Partition Table - Wikipedia

set id=ebd0a0a2-b9e5-4433-87c0-68b6b72699c7

NO Windows GUI partition tool allowed me to do this ONLY via M$ shell using diskpart !!!

Be careful using the shell utilities, they are very capable BUT it is not always obvious what to do - fairly primitive especially determining the correct disk/partition/etc especially if multi hdd multi partitions, etc !

Thx all

GPT specification was written under UEFI specification.
If you have a HDD bigger than 2.2T, legacy BIOS cant deal with it unless you load a software that makes two partitions and link them as one.
To use a GPT disk at all capacity, you must have your system running on a UEFI BIOS.
As your MB has a UEFI BIOS and Win 7 64 is UEFI compatible, you should have had windows installed as UEFI.

@IJustWantItToGo, Glad you could solve your problem yourself by changing the Partition ID. Well done and thanks for sharing that info.

There is a good article here uefi - How to change GPT partition type on windows? - Super User

"Using a combination of the set id TechNet article and detail partition, I discovered these common possible values:

• Recovery: de94bba4-06d1-4d40-a16a-bfd50179d6ac
• Normal: ebd0a0a2-b9e5-4433-87c0-68b6b72699c7
• EFI: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
• Reserved: e3c9e316-0b5c-4db8-817d-f92df00215ae

It's probably a good idea to consult the partition attributes for a partition of a certain type (look at a healthy computer) so the set flags make sense"

Basically you made all those partition IDs change by manipulating the drive in many ways that we - atleast me - could not track and understand. And so you were left to solve it yourself . And you did it.

Anyway, we learnt something by your experience.

Thx.

TBH, I did not change anything to cause the original issue - something occurred during that power glitch to cause the orig config to lose boot (MBR corruption?) - first for me ever - AC glitches happen - this the shortest ever - less than an eye blink - maybe M$ file caching is at issue but why ruin MBR ?

The GPT hdd that was the 'trouble' hdd was PURELY a data disk - never had a boot partition or used for such - 2 partition - #1 partition - 127mb, #2 partition - remainder of GPT 3TB hdd - SIMPLE.

How/why it was GPT 'EFI System' (which was the COMPLETE issue) I do not know, If it was before power glitch, then why was it not 'visible' after I finally fixed MBR to boot an installed Win 7 (having to go to a single hdd to correct boot issue) when re-added into system ?

All the other info was Background as was labeled - info 'possibly' important, but ended up confusing ppl - as I actually suspected it would - my mistake too much info confuses.

The REAL issue is why Microsoft has NO auto tools to 'fix simple boot' issues on multi hdd, multi boot systems (on diff hdds) - THAT WORK !!

Fixing MBR/Boot is Really a simple issue to fix IF M$ would allow 'help' from the user (I have had it find OLD OS installs but not current! OR not see restore points) - it seems so so blind at times and apparently wrong headed - automagic tools suck if STUPID - M$ boot repair can/is STUPID - Win 7 OR Win 10 versions.

So I learned something - each M$ OS failure teaches us - sad we must have to learn it though
!!

PCs are tools - I do not want to learn how to build my own screwdriver, nor should we have to know shell tools to simply BOOT !

Maybe so, but then this is at core, a 10 yr old machine/case, upgraded as time passed, new power supplies, new GPUs, new larger hdds, new OS, mixed age/size hdds, etc.

Of course when starting from scratch, the config of all should be the latest but if of mixed age and tech, not always possible - doing things with what you have is harder than starting over.

And honestly I think even with 2-3TB GPT hdds with 2.8TB partitions, I am still in IDE/legacy setting in BIOS - using a 2102 BIOS f/w version - the latest for my MB.

Such is life.

Megahertz07 said:

GPT specification was written under UEFI specification.
If you have a HDD bigger than 2.2T, legacy BIOS cant deal with it unless you load a software that makes two partitions and link them as one.
To use a GPT disk at all capacity, you must have your system running on a UEFI BIOS.
As your MB has a UEFI BIOS and Win 7 64 is UEFI compatible, you should have had windows installed as UEFI.