How to check how long your Mac has been running, and when to restart
uptime shows how long since the last restart. Ours had run 1 day 6 hours with 4 GB of swap built up. How to check it and why a restart now and then helps.
How do I check uptime?
uptimeOurs printed up 1 day, 6:02, 1 user, load averages: 2.29 3.56 4.56. System Information, Software, also shows Time since boot.
| After 30 hours on our Mac | Value |
|---|---|
| Swap used | 4.16 GB |
| Processes | 537 |
| Threads | 3,500 |
Does a Mac need restarting?
Not on a schedule. macOS manages memory well over long uptimes. A restart helps when swap has grown large, an app or system process misbehaves, or an update is waiting. It also clears swap files and the sleep image from disk; see swap used.
See it live
Free Mac's System tab reads processor, memory, network and battery once a second, with the busiest processes ranked below, and every tile opens into detail. See also how many processes run on a Mac.
Related: How many processes does a Mac run and Why can't I quit a process on my Mac.
Common questions
How do I check uptime on a Mac?
Run uptime in Terminal, or look at Time since boot in System Information, Software.
How often should I restart my Mac?
When something calls for it: large swap with slowdowns, a misbehaving process, or a pending update.
Does restarting a Mac free up space?
It clears swap files and temporary files, which can be gigabytes.