Thanks for the advice regarding Grammarly. I use it all the time, though it is one of the most frustrating apps. Grammarly finds spelling errors that Apple's "spell check" misses 90% of the time. However, with Sequoia, Grammarly ran 100% fine without any of the issues I am experiencing now.
So, what was it with Tahoe that caused this, according to the LLM?
"That’s a really good question — and it’s the root cause of everything you’ve been fighting (slowness, bloated System Data, swap spikes, even kernel panics).
Let’s unpack this clearly.
💥 Why macOS Tahoe broke things on your M3 Mac (8 GB RAM)
1. Tahoe’s memory pressure
Tahoe (macOS 15) introduced new background frameworks — notably the Apple Intelligence / Spotlight intelligence layer — which keep large neural, indexing, and language-model caches in memory.
On systems with only 8 GB of unified memory, that extra background activity pushes the Mac into swapfile overdrive(writing chunks of memory to SSD).
- Each swapfile can reach 2–4 GB.
- macOS keeps several active at once (/private/var/vm/swapfile0…).
- This easily balloons “System Data” by tens of gigabytes.
Result → the SSD fills, the system thrashes, and responsiveness collapses.
2. Virtual-memory feedback loop
When free space gets tight, Tahoe constantly creates and deletes swapfiles, caches, and log data.
That creates a vicious cycle:
swap → disk I/O → heat → lag → watchdog timeouts → occasional kernel panics
This effect is mostly invisible in the GUI but obvious in Terminal (vm_stat, df -h).
3. Broken or failed updates left sealed snapshots
Tahoe’s updater writes a complete copy of the system into a sealed APFS snapshot before switching boot volumes.
If an update fails or you roll back (as you did to Sequoia), those snapshots remain marked “non-purgeable.”
Each snapshot can occupy 20–60 GB of hidden space that “Storage → System Data” reports but Finder can’t see.
That’s exactly what you found and deleted earlier.
4. Indexing never finished
Because the system was starved for memory and I/O, Spotlight and Photos indexing kept restarting.
Those temporary databases live in /private/var/folders/ and /private/var/db/Spotlight, inflating “System Data” even further.
5. Resulting symptoms
- Massive “System Data” (60 GB +)
- Slow Safari, Finder, and app launches
- Frequent swap use on a small SSD
- Occasional kernel panics from low-level I/O stalls
None of this was hardware failure — it was Tahoe’s resource demands exceeding the physical limits of 8 GB Macsplus residual snapshots clogging your APFS container.
✅ Why Sequoia fixed it
- Sequoia’s clean install removed all stale snapshots and swap caches.
- Its background daemons are calmer (Apple throttled the AI components when RAM ≤ 8 GB).
