I have a new LaCie 1TB hard drive. I erased and formatted it to use as a Time Machine backup but first I want to partition it so I have a little extra space for moving a few files around. Partition is greyed out in Disk Utilities.
MacBook Air 13″, macOS 14.4
Please provide a screen shot of what you are seeing in the Disk Utility.
Be sure to set "Show All Devices" for the utility's View setting ... and then, select the LaCie drive BEFORE making the screen shot.
We plugged it into another Mac last night, which didn't seem to change anything, but I just tried again in my Mac and it worked. It finally allowed me to select GUID partition and then to format for APFS - something I knew nothing about until this journey. Now I will add another APFS volume rather than partition, which is what Apple seems to recommend, and I should be OK. So no screenshots needed after all, at least as of now, and I very much thank you for your jumping in to help.
You're very welcome. I'm glad you got it worked out.
Disk utility partition greyed out
