Leaving the Claude App Open Can Freeze Your Mac: The Checklist That Stops the Memory Leak
Leave the Claude desktop app running for hours and it can eat more memory than your Mac has, push everything onto your SSD and freeze the whole computer until you hold the power button. What's actually leaking, how to spot it in ten seconds, and the checklist to run before every long session.
You leave the Claude app open while it works, come back, and nothing moves. The cursor spins, apps won't quit, and the only way out is holding the power button, which loses anything you hadn't saved. Reports on Anthropic's own GitHub describe exactly this: the Claude desktop app on a Mac climbing past 100 GB of memory until macOS says "Your system has run out of application memory" and stops responding.
Here's what's leaking, how to catch it before it freezes, and the checklist that keeps it from happening.
Why it freezes
Memory is the space your Mac needs to keep apps running. When an app keeps taking more and never gives it back, that's a memory leak. Once memory runs out, macOS starts borrowing space from your SSD (it's called swap) and squeezing what's left. Everything slows to a crawl, and past a point the whole Mac locks up.
The reports on Anthropic's GitHub show where it comes from:
- The desktop app itself. One Mac with 48 GB of memory watched Claude Desktop grow to 131-140 GB, three times, and freeze. The same work in Claude Code in the Terminal stayed under 200 MB.
- Leftovers that keep running. Background processes started by Claude Code sessions (MCP servers, a browser tool, helper scripts) kept running after the sessions went quiet. Overnight, with the lid closed, memory climbed about 100 GB in under an hour and swap hit 46 GB before the Mac hung.
- One hungry MCP server. A single MCP server grew to 30 GB on a 16 GB MacBook Air, with swap 75% full.
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Get the full setup steps + the copy-paste setup prompt
The rest of this guide (5 more sections) opens right here. The setup prompt, one paste into Claude that sets it all up, comes by email only. Use your real address.
Unlocks: Step 1: the ten-second check · Step 2: the checklist before every long session · Step 3: before you walk away (or go to bed) · Step 4: if it freezes anyway · The honest notes
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