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On the main dashboard of your macOS, open the Finder app and access the Utilities folder.Here’s are some quick step-by-step instructions that will walk you to the process of forcing the system to create a new partition map via Disk Utility: Creating a New Partition Map via Disk Utility Since there are 2 different ways that will allow you to do this, we’ve put together 2 different sub-guides that will walk you through the process of creating a new partition map.įell free to follow whichever one is closer to your preferred way of troubleshooting macOS issues:Ī. This is confirmed in situations where the Couldn’t modify partition map error is being caused by a system action that ends up corrupting the partition map. Now that you are aware of every scenario that might trigger the Couldn’t modify partition map error, here’s a list of methods that might allow you to fix it: Method 1: Creating a New Partition MapĪs it turns out, a lot of affected users that were also dealing with this issue on macOS have managed to fix the issue by using Disk Utility to create a new partition map by forcing the utility to show all devices and erasing the problematic partition. If this fails, you should attempt to mont a healthy macOS state via the Time Machine utility. In this case, you should be able to fix the issue by initiating a repair disk operation via the Recovery Menu. Corrupted OS files – Under certain circumstances, you can expect to see this issue occurring in situations where you’re actually dealing with some type of system file corruption that is affecting the reformatting operation.
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In this case, you need to flip the Locked/Unlocked switch in order to fix the issue.
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