Missing partition on bootcamp windows after update on MAC OS side

Nick Perks
Nick Perks used Ask the Experts™
I have a Mac book pro which was running on old version - 10.9.7 with Windows running on boot camp. I am not familar with MAC side and always used windows only on this mac.

Recently, due to some issues on my iphone, had to take my phone and mac to apple store which ended up doing a big update on my mac i believe to version 10.13.7 and helped with my iphone restoral which was successfull.

I came home and logged in to windows and noticed that one of the partition on my windows side disappeared i.e Z drive. I originally had C drive and Z drive. I am not really concerned about the data on my Z drive as i do have it backed up but I am curious what happened to it ?  I checked disk management on windows and there is no partition.

I logged into mac side and could only see two drives BootCamp drive ( c drive of windows ) and the Mcintosh HD drive. It is as if my Z drive partition completely disappeared.

Two questions at this point:

1. Any idea what could have happened to my Z drive ? How can this just disappear ?  Is there something simple I am missing.

2.  Inorder to get Z drive back, I started process of Partitioning my Macintosh drive ( Currently 400 GB into 150 GB for Macintosh drive and 250 for new created Z drive )
     Its currently running the process and applying changes to the harddrive.

It is now stuck on this checking object map for about 3 hours now and I am concerned is it even doing anything ?  Mouse cursor is still accessible.


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That looks like a fsck disk scan, not a partition.  If it's stuck there, it's trying to "fix" a broken file system object.

OS X 10.13 changes the Mac files system from HFS+ to APFS.

What format was your Z: drive.  OS X only recognizes a single partition for bootcamp.  If you created a 2nd partiition, it should still be NTFS, unless you changed it to EXFAT.
Nick PerksIT Director


Actually while repartitioning the existing MAC drive, I choose the exfat option on the new partition drive that I created. Could it be the reason it's taking forever ?
It should not take forever to partition the disk.  You're scanning the disk, and that will take forever if there are errors.  How old is the disk?
Nick PerksIT Director


4 years old laptop - Samsun SSD 850 EVO.

once again, SInce there was only 1 Macintosh HD drive, I initiated the process to repartition this MAC drive which had about 120 GB data on it.

Total MAC drive 351.65 GB  - 120 used and rest free
Started process to leave 150 GB on this MAC drive and create a new partition of the remianing drive i.e 201.65 GB and format it as exfat. This new partition once created I plan to use on windows side

Its been 5 hours now and its stuck on this screen. I am scared if I terminate this process it could corrupt the harddrive.

Would you recommend me leaving this process overnight or try terimate it and retry ?

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