jerryc41 Loc: Catskill Mts of NY

I have a 750GB drive that was used on a Mac, and I'd like to use it on a Windows machine. Using Disk Management, I was able to delete the main partition and format it in my Dell. There is a bit left over - 200MB - that I cannot access. Is there a way to delete whatever the Mac put there so I can use the entire drive? Diskpart doesn't seem to offer a solution. It shows the 698GB drive.

burkphoto Loc: High Point, NC

Are you seeing real GB or Marketing GB? Real GB are based on powers of 2, while Marketing GB are base 10 numbers (fewer bytes to make a GB).

In any case, you need a low level formatting device that can erase the entire drive. Apple Disk Utility should be able to do that. I am not sure what utility you need for Windows, but the format it creates needs to be NTFS, not APFS or MacOS Extended.

jerryc41 Loc: Catskill Mts of NY

I'm see the GB the computer shows me. Since it's a "750GB" drive, dividing 750 by 1024 would give 732GB as the actual capacity. The computer is showing 698.44 in that sector, with 200MB in the other, inaccessible sector. I'll connect it to a Mac later and see if that can do anything. 200MB compared with 698GB isn't much, but if I can use it, I'll use it.

I find it ironic that in a field as technical as computers, they can't agree on how large a MB is. It would be like having two different speeds for MPH. Were you really speeding? Maybe you were just using the other system.

therwol Loc: USA

The "heavy artillery" method described about half way through this article may help. I've done it once, and it worked for me.

https://www.winability.com/force-diskpart-delete-remove-efi-system-partition-windows-10/

burkphoto Loc: High Point, NC

That 200MB is probably the Mac EFI (Electronic Firmware Initialization sector). It loads first on startup if there's a system on the drive.

BigDaddy Loc: Pittsburgh, PA

Win, strange enough, uses the FORMAT application to format a disk. You don't need to use NTFS, but is is the most common for todays large drives.
As far as "Marketing" GB vs "Real" GB there is no such thing. "REAL" GB is 1 Billion bytes. Computer folks sometimes alter the meaning of K, M and Gig and use binary math instead of standard math, so a K might mean 1024 instead of 1000. 1024 fits binary numbers better than standard numbers if your doing binary math, which not many people do, not even many computer folks. It's not a marketing gimmick, it's an ease of use vocabulary perversion, common in all fields of endeavor. Reminds me of people getting all fired up over 2x4's not actually being 2"x4". People in the biz understand dimensional lumber and some even understand how those sizes came about.

Someone actually sued a big box company because their 2x's were not really 2 inches. They lost and so would someone suing over the "Marketing" meaning of Gig vs the "Real" meaning.

At any rate, that's not likely the reason for the missing 200 gigs or whatever. Most likely is it's in a different partition that wasn't accounted for when formatting, or, unlikely but possible, the drive has bad sectors that were marked unusable when formatting.

jerryc41 Loc: Catskill Mts of NY

This drive was used with Time Machine on a Mac desktop.

burkphoto Loc: High Point, NC

Then that’s the EFI partition from the backup. TM backs that up.

jerryc41 Loc: Catskill Mts of NY

That makes sense. Will I be able to delete that using a Mac?

burkphoto Loc: High Point, NC

Re-partition the drive to make one big partition. Then use Format in Windows. That should do it.

jerryc41 Loc: Catskill Mts of NY

Thanks. I've been working on other projects, but I'll get to it.

therwol Loc: USA

Jerry, I've found the reason for all of the trouble you have with electronic devices. Your house is a magnet for cosmic rays. You can establish this by moving to another house. Let us know the outcome.

https://www.bbc.com/future/article/20221011-how-space-weather-causes-computer-errors

traderjohn Loc: New York City

I think you it the nail on the head.

Harry0 Loc: Gardena, Cal

Sometimes for certain format options Windows will leave a partition portion as a "spare" space.
Windows 10 calls it a "recovery" partition. Sometimes it is. But not like a Mac's.
My 2tb Firecuda boot disk (on this machine) has a 839,b one, 340 free,
My wife has a 1tb ssd with a 430mb extra.
Some OEMs will have these- you actually boot from them.
Some OEMs will have these- you actually have system recovery tools hidden in there.
There might be a valid reason for this. I'd leave it.

jerryc41 Loc: Catskill Mts of NY

And all this time I thought it was because of the Indian burial ground and the spot where many witches were put to death. Live and learn!

That space weather article is scary.