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Reply To: [Solved] MacBook Pro 16″ M2 Max Thunderbolt 4 SSD Speeds Throttled to USB 3.0 (macOS Sequoia 15.1) – Verified Troubleshooting

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Home › Forums › MacBook, iMac & macOS Lab › [Solved] MacBook Pro 16″ M2 Max Thunderbolt 4 SSD Speeds Throttled to USB 3.0 (macOS Sequoia 15.1) – Verified Troubleshooting › Reply To: [Solved] MacBook Pro 16″ M2 Max Thunderbolt 4 SSD Speeds Throttled to USB 3.0 (macOS Sequoia 15.1) – Verified Troubleshooting

November 14, 2026 at 11:31 pm #14622
Noah Crawford
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:

  1. Verify cable has official Thunderbolt 4 lightning bolt and ‘4’ logo. Charging cables will not negotiate PCIe.
  2. Reset bus enumeration: sudo killall -9 diskarbitrationd.
  3. Enable APFS TRIM support: sudo trimforce enable.

Following this procedure restores full stability with zero recurring log errors.

Mac mini M2 Pro (32GB) | Dell UltraSharp U3223QE | Jamf Cloud Admin | Glasgow, UK
Apple Certified Support Professional (ACSP) | Enterprise Mac Sysadmin & Jamf Pro Architect