Mac log files: where they are and which are safe to delete

Part of: What can I safely delete on my Mac? Safe, risky and never (Safe to delete)

Old log files are safe to delete, mostly. They are plain records of what apps did, and apps write new ones when they need to. You only lose history that helps when diagnosing a problem. Logs also rarely take much space, so check the size first.

Where logs live

Three places matter:

• ~/Library/Logs: logs from your own apps and tools. This is the one to look at.
• /Library/Logs: logs shared by the whole Mac, written by system-level software.
• /private/var/log: logs from system services, managed by macOS.

Crash reports are kept in a DiagnosticReports folder inside ~/Library/Logs, and in the same place under /Library/Logs.

Check the size of your user logs with this read-only command:

du -sh ~/Library/Logs

List what is inside, largest last:

du -sh ~/Library/Logs/* | sort -h

To open the folder in Finder:

open ~/Library/Logs

What you lose by deleting logs

A log is a history, not something the app needs to run. If you delete one:

• The app creates a new log next time it writes one.
• You lose the record of past errors. That only matters if you are chasing a problem right now, or if someone, like a support team, asks for the log.
• Crash reports for old crashes are gone.

Nothing stops working, and no data is lost. If you are in the middle of troubleshooting, keep the logs until you are done.

What to leave alone

• System logs under /private/var/log and /Library/Logs. macOS rotates and removes old entries itself. These folders may need administrator rights, which is a sign they are not yours to tidy.
• A log an app is writing right now. Quit the app first, or leave that file.
• Folders that are not logs. Some apps keep other data in a folder named Logs. If a name does not look like a log file, open it before you decide.

How to remove old logs

1. Run du -sh ~/Library/Logs/* | sort -h and look at the largest items.
2. Quit the apps that own them.
3. Move the old files to the Trash. Keep recent ones if you are chasing a problem.
4. Empty the Trash. The space comes back only then. See why the Trash does not free space.

Do not expect much. If your total is small, other folders are a better use of your time, such as caches.

What crash reports are for

When an app crashes, macOS can write a short report in DiagnosticReports. Developers use these to find bugs, and the reports can be sent to Apple or to the app’s maker. Once a crash is fixed or forgotten, the report has no further use on your Mac. Each file is small, and a long-lived Mac can still collect a lot of them. If the same app keeps crashing, keep its recent reports until you have told its developer or found a fix.

The Safe / Risky / Never box

Why deleting logs rarely helps

On many Macs, logs are small compared with caches, app data or media. That is why this is rarely the first thing to clear. Look at the size first, as above. If it is tiny, leave it and look for bigger things in What can I safely delete on my Mac?.

Common mistakes

• Treating logs as the main space hog. Check the size first. Most of the time, caches or app data are far larger.
• Deleting logs before sending them to support. Keep them until the case is closed.
• Removing system log folders with administrator rights. macOS rotates its own logs. Hand-deleting them gains little.
• Leaving the app open. An app that is writing a log can keep the file in use.

Quick checklist

1. Check the size with du -sh ~/Library/Logs.
2. If it is small, skip this and look at larger folders.
3. If it is large, find the biggest files and quit their apps.
4. Move old files to the Trash, then empty it.

Check what is large

DiskJoy is our product. It scans your disk and shows reclaimable space by category, including logs. It is read-only today, and cleanup is not available yet. The scan can show whether logs are worth your time on your Mac.