slow boot from external drive

Hi all, I have Mac mini M4 with 16GB RAM and 256GB drive, so I installed the OS on external drive after fresh install it takes 30 sec to boot even after I have few apps enabled at startup , but as and when I update the OS , with each update it adds 30 to 50 seconds to boot time, after few updates it takes up to 5 mins , but if I erase the disk and install the latest OS again and restore the data from backup it's back to 30 seconds boot. anyone else experienced this ?

btw this is on both 26 and 15.7 version of macOS.

Mac mini, macOS 26.0

Posted on Oct 18, 2025 2:25 PM

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neuroanatomist

Level 9

55,683 points

Posted on Oct 19, 2025 8:00 AM

Is FileVault enabled? It’s turned on by default in Tahoe. Modern Macs have hardware-supported encryption/decryption for internal storage, but if your OS is on an external drive the decryption will be (relatively) much slower.

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17 replies

Oct 19, 2025 8:13 AM in response to neuroanatomist

FileVault is disabled

Oct 19, 2025 6:45 AM in response to iPhoneSE16Dream

iPhoneSE16Dream wrote:

Hi all, I have Mac mini M4 with 16GB RAM and 256GB drive, so I installed the OS on external drive

Typically, a much better strategy is to keep macOS and your applications on the internal storage, and attach external storage for data/files/etc.

slow boot from external drive