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Reply To: [Solved] Mac mini M4 Pro Thunderbolt 4 SSD Speeds Throttled to USB 3.0 (macOS Sonoma 14.6.1) – Verified Troubleshooting
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Home › Forums › MacBook, iMac & macOS Lab › [Solved] Mac mini M4 Pro Thunderbolt 4 SSD Speeds Throttled to USB 3.0 (macOS Sonoma 14.6.1) – Verified Troubleshooting › Reply To: [Solved] Mac mini M4 Pro Thunderbolt 4 SSD Speeds Throttled to USB 3.0 (macOS Sonoma 14.6.1) – Verified Troubleshooting
November 15, 2026 at 12:32 am
#15629
Alexander Woods Certified Tech (Lvl 5)
Apple Recommended / Verified Community Solution
This canonical solution was verified and marked as solved in the Apple Support Community archive.
Verifying certified 40Gbps active cables, resetting Thunderbolt kernel extensions, and enabling TRIM.
Here is the exact step-by-step diagnostic and remediation procedure verified by Apple Certified Support Professionals:
- Verify cable has official Thunderbolt 4 lightning bolt and ‘4’ logo. Charging cables will not negotiate PCIe.
- Reset bus enumeration:
sudo killall -9 diskarbitrationd. - Enable APFS TRIM support:
sudo trimforce enable.
Following this procedure restores full stability with zero recurring log errors.
Mac mini M4 Pro (48GB) | Studio Display | HHKB Professional Hybrid | Auckland, NZ
Apple Certified Support Professional (ACSP) | Computer Science & Machine Learning Student