Several utilities access the log. When there are problems getting entries, they each report details. Here’s what each error report means, and what you can do to fix it.
LogUI
Log entries mentioning errors are common and can mislead. Those marking the consequences of errors may not mention the word error. Turn detective to work out where the error really is with these tips.
What happens when you can’t solve a problem, so you get a log extract and ask Claude to diagnose it for you? Here’s a full worked example.
Displays emoji to indicate the type of each log entry, improves export as Rich Text, and augments fields when copying entries.
Apparently based on Mach absolute time, log entry times are converted to wallclock times. This exposes them to the vagaries of time zones, seasonal adjustments, and periodic wallclock adjustments. Here’s how all that works, and can confuse.
How to combine the time of interest with waypoints to reduce 100,000 log entries to just a handful, and discover what you’re looking for in the log.
The four types of log entry, all the fields they can contain, and those they are likely to include, shown in the order and colour scheme used in LogUI. Censorship and how to disable it, with a signed profile to do so.
Build 74 adds a Diagnostics Tool to analyse and catalogue diagnostics folders that are or have been a live log store, including those saved in backups.
Log entries are purged from storage according to elaborate rules explained here, for different types of log entry. How to extend time coverage in those logs, and how to get free statistics about them.
What you can learn from browsing the log, and why it’s so important in diagnosis and troubleshooting, research into macOS, and measuring performance. With a worked example.
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