I have a few problems with a 2012 era macbook air. the first problem, and i'm not sure how to go about fixing this, is an issue i'm dealing with re: EFI. When i select the hard drive in disk utility and attempt to verify it, I get the following error:
"Problems were found with the partition map which might prevent booting Error: This disk doesn’t contain an EFI system partition. If you want to start up your computer with this disk or include it in a RAID set, back up your data and partition this disk."
the second problem is trying to reclaim a missing 20GB of space that went missing when i deleted a failed Windows partition. The space just vanished, poof! You can see it in the diskutil list below.
#: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.3 GB disk0 1: Microsoft Basic Data EFI 208.7 MB disk0s1 2: Apple_HFS MacOS 479.0 GB disk0s2 3: Apple_HFS Recovery HD 650.0 MB disk0s3
gpt -r show /dev/disk0
start size index contents 0 1 PMBR 1 1 Pri GPT header 2 32 Pri GPT table 34 2014 2048 407552 1 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 409600 40 409640 935546880 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC 935956520 1269544 3 GPT part - 48465300-0000-11AA-AA11-00306543ECAC 937226064 39878963 977105027 32 Sec GPT table 977105059 1 Sec GPT header
diskutil resizevolume disk0s2 limitson the two volumes (
disk0s3 respectively) and they returned as follows:
For device disk0s2 MacOS: Current size: 479.0 GB (479000002560 Bytes) Minimum size: 446.3 GB (446258642944 Bytes) Maximum size: 479.0 GB (479000002560 Bytes) For device disk0s3 Recovery HD: Current size: 650.0 MB (650006528 Bytes) Minimum size: 650.0 MB (650006528 Bytes) Maximum size: 20.9 GB (20933816320 Bytes)
am i correct in reading this, that the missing 20 GB somehow ended up on the recovery HD?
so what's the first thing i should do? i want to keep my OS running on 10.9.5. I have a diskImage i downloaded from the internet, put onto a USB boot drive. I attempted to reinstall from this boot drive, to see if this would fix anything, but when i try to select the macOs, i get the error, "this disk cannot be used to start up your computer"
Besides this, the computer seems to operate fine, and has been working since april with this broken EFI and missing partition space.