HomeTechnologyMac prohibitory symbol: Causes, Alternatives, and fixes

Mac prohibitory symbol: Causes, Alternatives, and fixes [Solved]

Mac prohibitory symbol indicates that the MacOS store on the startup disc is not compatible with Mac’s current model or version. This symbol shows on startup because the device fails to detect the operating system in the startup disk.

Causes of Mac prohibitory symbol

The major reason for this sign of trouble on a Mac is the existing unsupportable Mac operating system on the startup drive. The second cause is capable MacOS is not found on the device.

How to fix Mac prohibitory symbol

Here are several ways to fix this error on MacBook, few best strategies to repair the prohibitory symbol on Mac, are mentioned below:

Method 1: Use the “Disk Utility” option to repair the mac prohibitory symbol

Rebooting the Mac in recovery mode and utilization of Disk Utility, fix the problems in the system drive.

This feature is listed in the macOS utility menu. Disk Utility is a helpful technique to settle issues in Mac, Using this helping component adheres to the guidelines underneath:

Push and hold down Mac’s force button for no less than 10 seconds it will make the power Mac turn off.

After 30 seconds, press the power button to switch it back on. Quickly snap and hold the ‘Command’ and ‘R’ keys together for around five seconds or somewhat more to start macOS in recovery mode.

The macOS utility work gives choices for doing various tasks. Select ‘Disk Utility’ to complete the startup disk fixes.

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The left half of the Disk Utility menu shows all accessible drives on your Mac. The primary drive alternative is the startup disk. For the startup disk, start your fix by choosing the last alternative in the disk menu. Snap-on the ‘First aid’ button to begin fixing.

Method 2: Updated or install macOS

If the prohibitory symbol Mac shows an error after a recently updates Mac or trying to install updated files, incomplete updates or installation can be a cause of this error.

Actually, sometimes the laptop automatically gets forced to restart due to a glitch, and this incomplete setup or installation starts to show Mac prohibitory symbol. Updating the OS again or Reinstalling the updated version is the only solution for this issue.

Method3: Boot Mac from an External Drive or Alternate Startup

A damaged hard disk is the other major cause of prohibitory signs on your MacBook. Hard disk crash, damage if it slips, or fell-down on the ground or on a solid surface.

In the rear case, displacement of hardware also damages Startup Disk. In case of a startup disk crash, macOS fails to locate or detect the system folder, and this prohibits users to access the device.

To access an internal startup disk, install macOS on an external hard disk and try if successful reach files or folder congratulation else your startup drive is damaged and needs to change.

Method4: Restore PRAM

PRAM stands for parameter random access memory. In mac, this is powered by a small battery and installed to store- important information about control settings and using this method this is assuming that the system will reboot properly.

Sometimes, your Mac might have one or two processes that are not up and running. These processes might be essential for booting your Mac. Force resetting the PRAM might help resolve that issue.

To proceed with this method, press and hold the combination of ‘Command’, ‘P’, and ‘R’ keys, immediately after you click the power button to start your Mac.

The combination of these keys will continually make your system reset while you hold down those keys. After 2-3 times reboots, you can release these keys, and let your Mac restarts.


The mac prohibitory symbol is a large grey circle with a diagonal line across the middle of it

This issue can avoid by mind some precautions before reinstallation of macOS such as Check Disk space for reinstalling macOS.

In this fix Mac prohibitory symbol guide the best working ways reveal, but it doesn’t mean other ways don’t work, you can try other methods also.


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