I tried APFS nothing its says can't change partition map or size not valid for file system chosenSo what is happening? Is it not offering APFS as an option? Does it fail when you try it?
From what I know about FAT32, I'm surprised that FAT12 would ever be an option.
HiYes. @mfram speaks true. Open Disk Utility, in menu View > Show All Devices.
This is the way.
diskutil list to find the ID of the drive, e.g. "disk4". Then use sudo dd if=/dev/zero of=/dev/rdisk4 bs=1m to write zeros to the drive. You will only need to let that run for a couple of seconds (enough to wipe out the partition table) then you can abort with Ctrl-C. Disk Utility should then let you partition it.Yes its read only and since it won't mount I don't know how to fix itThen we're going to need screenshots showing the whole window and what you're clicking on. I supposed it's possible if you wrote an ISO image that somehow the device appears as read-only now.
Tried on two different computers 3 times no effectWipe it out with Terminal. Dismount (not eject) through Disk Utility if it's mounted, then pop into Terminal. Rundiskutil listto find the ID of the drive, e.g. "disk4". Then usesudo dd if=/dev/zero of=/dev/rdisk4 bs=1mto write zeros to the drive. You will only need to let that run for a couple of seconds (enough to wipe out the partition table) then you can abort with Ctrl-C. Disk Utility should then let you partition it.
Trying to repartition and reformat the USB after using it as a Linux install disk. I've tried under Mac os sonoma and ubuntu but no luck. Near as I can tell the USB is set to read onlyScreenshots, need more screenshots...
Or better yet, a video recording...
Are you trying to erase/format a flash drive [USB stick] or the internal storage [hard disk/solid state drive]?
Are you trying to erase it within Disk Utility while running macOS or Disk Utility while on Recovery?
You can only erase/format it as macOS extended [HFS+] or APFS [High Sierra or newer] using a Mac but you can erase/format it as MS-DOS FAT/FAT32 using Windows or Linux or macOS...
Yes I tried erase it failed with error -69825. There is no switch on this USBThe 4th screenshot [with Disk Utility showing], did you try clicking Erase at the top and did it still give you an error?
The View drop down on the upper left, did you set it to Show All Devices? Based on the screenshot it seems to be, but just confirming...
In Disk Utility in El Capitan [10.11] and newer, you need to erase [format] first before you can partition the drive/disk...
In Disk Utility in Yosemite [10.10] and older, you can partition the drive/disk before erasing [formatting] it first...
Do you notice any switch that might have made the USB stick read-only? Make sure it is set to unlocked...
Something like this:
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Usually a count=16 is enough with a block size of 1MB.You will only need to let that run for a couple of seconds
Good to know! I should actually read the documentation at some point and learn about these extra parameters 🙂Usually a count=16 is enough with a block size of 1MB.
That failed as well. Says error writing leading zeros.I have solved this problem before using sd card formatter when nothing else would work.
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SD Memory Card Formatter for Windows/Mac - SD Association
Watch our video on how to use the SD Memory Card Formatter SD Memory Card Formatter 5.0.3 for SD/SDHC/SDXC/SDUC The SD Memory Card Formatter formats SD Memory Card, SDHC Memory Card, SDXC Memory Card and SDUC Memory Card (respectively SD/SDHC/SDXC/SDUC Cards) complying with the SD File System...www.sdcard.org