Mac OS X磁盘重新分区后 BootCamp Windows启动项丢失

前言

我有一台Mac，装有OS X和Windows两系统，因Windows和OS X都能读写exFAT分区，

故若在Machintosh HD和Windows HD之间开辟一个exFAT分区，可以作为共享文件区。

我在OS X中用磁盘工具对Machintosh HD进行分区，在Machintosh HD和Windows HD之间开辟一个exFAT分区。

重启启动时，我按住了option，之后出现的启动选项中没有Windows。这因为刚才给磁盘分了区才导致的。

解决

重启MAC ，按住COMMAND+R进入恢复模式，打开Terminal

csrutil disable #关闭rootless

修改完，重启MAC，打开终端

sudo fdisk -e /dev/disk0

yanghaodeMacBook-Pro:~ yanghao$ sudo fdisk -e /dev/disk0
Password:
fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
Enter ‘help‘ for information
fdisk: 1> p
Disk: /dev/disk0    geometry: 30515/255/63 [490234752 sectors]
Offset: 0    Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
 2: AC 1023 254  63 - 1023 254  63 [    409640 -  183869624] <Unknown ID>
 3: AB 1023 254  63 - 1023 254  63 [ 184279264 -    1269536] Darwin Boot
*4: 07 1023 254  63 - 1023 254  63 [ 185548800 -  304685056] HPFS/QNX/AUX
fdisk: 1>    

修改分区表

fdisk: 1> p
Disk: /dev/disk0    geometry: 30515/255/63 [490234752 sectors]
Offset: 0    Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
 2: AC 1023 254  63 - 1023 254  63 [    409640 -  183869624] <Unknown ID>
 3: AB 1023 254  63 - 1023 254  63 [ 184279264 -    1269536] Darwin Boot
*4: 07 1023 254  63 - 1023 254  63 [ 185548800 -  304685056] HPFS/QNX/AUX
fdisk: 1> setpid 4
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
*4: 07 1023 254  63 - 1023 254  63 [ 185548800 -  304685056] HPFS/QNX/AUX
Partition id (‘0‘ to disable)  [0 - FF]: [7] (? for help) 07
fdisk: 1> flag 4
Partition 4 marked active.
fdisk:*1> p
Disk: /dev/disk0    geometry: 30515/255/63 [490234752 sectors]
Offset: 0    Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
 2: AC 1023 254  63 - 1023 254  63 [    409640 -  183869624] <Unknown ID>
 3: AB 1023 254  63 - 1023 254  63 [ 184279264 -    1269536] Darwin Boot
*4: 07 1023 254  63 - 1023 254  63 [ 185548800 -  304685056] HPFS/QNX/AUX
fdisk:*1> write
Device could not be accessed exclusively.
A reboot will be needed for changes to take effect. OK? [n] y
Writing MBR at offset 0.

 重启电脑按OPTION

原文地址：https://www.cnblogs.com/xiao-apple36/p/8907965.html