Resolving Performance Issues on Mid-2012 MacBook Pro After Sequoia Upgrade

Your Mid-2012 MacBook Pro with 16GB RAM and a 750GB HDD was likely struggling due to the demands of macOS Sequoia, which is optimized for more modern hardware. The HDD, in particular, can become a bottleneck for newer macOS versions that rely heavily on fast storage (APFS is especially demanding on HDDs). Here’s how to proceed:

Immediate Options: Roll Back or Fresh Install?

1. Roll Back to macOS Big Sur (Recommended)

• Why Big Sur?

  • You mentioned that Big Sur was performing well on your system.
  • It’s optimized for older hardware and strikes a balance between modern features and performance.

• Steps to Roll Back to Big Sur:

  1. Backup Your Data:
     • Use Time Machine or another external drive to back up important files.
  2. Create a macOS Big Sur Installer:
     • On another Mac:
       • Download Big Sur from the Apple Support page.
       • Use the createinstallmedia Terminal command to make a bootable USB installer:

         bash
         Copy code
         sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/YourUSBDrive
         

  3. Erase the Disk:
     • Boot from the USB installer by holding Option (⌥) at startup.
     • Open Disk Utility and format the internal drive as APFS (GUID Partition Map).
  4. Reinstall Big Sur:
     • Install macOS Big Sur and restore your data from backup.

2. Roll Back to macOS Monterey or Sonoma

• Why Consider Monterey?
  • It’s more modern than Big Sur but slightly lighter than Sequoia.
  • It supports most Big Sur features but with better app compatibility.
• Sonoma?
  • Only consider Sonoma if you’re committed to newer macOS features and plan to upgrade to an SSD.

3. Wait for Patches or Updates (Not Recommended)

• Why Not Wait?
  • If performance issues stem from the HDD or hardware limitations, patches won’t resolve the root cause.
  • Sequoia's demands are too high for your current configuration, especially with an HDD.

Performance Optimization for macOS Sequoia

If you decide to stick with Sequoia temporarily, try these steps to optimize performance:

1. Upgrade to an SSD (Highly Recommended)

• Why?
  • macOS Sequoia heavily relies on APFS, which performs poorly on HDDs.
  • An SSD will drastically improve boot times, app loading, and overall responsiveness.
• Best Option:
  • Replace the 750GB HDD with a 500GB or 1TB SSD (e.g., Samsung 870 EVO or Crucial MX500).
  • Use macOS Migration Assistant to transfer your data.

2. Perform a Fresh Install of Sequoia

• Upgrading from Big Sur directly to Sequoia can introduce issues due to leftover system files or configurations.
• Steps:
  1. Create a Sequoia installer on a USB drive (as described above).
  2. Format the drive and perform a clean installation.

3. Free Up Storage

• Ensure at least 20-30% free disk space to allow macOS and apps to work efficiently.
• Remove unnecessary files or use tools like CleanMyMac.

4. Disable Visual Effects

• Go to System Preferences > Accessibility > Display:
  • Check Reduce Motion.
  • Check Reduce Transparency.

5. Disable Spotlight Indexing (Temporary)

• Spotlight indexing can bog down HDDs during the initial post-install phase.
  • Run this command in Terminal:

    bash
    Copy code
    sudo mdutil -a -i off
    

  • Turn it back on after other optimizations:

    bash
    Copy code
    sudo mdutil -a -i on
    

Final Recommendation

1. Best Solution: Roll back to macOS Big Sur or Monterey. Both are better suited for your current hardware, especially with an HDD.
2. Upgrade Option: If you’re willing to invest, upgrade to an SSD and reinstall macOS Sequoia or Sonoma for a modern experience.
3. Avoid Waiting: Sequoia is unlikely to improve significantly on your hardware with patches alone.

Let me know if you need detailed steps for any of these options!