Question: Q: What do the following log messages mean?

shaofeng0956 wrote:

log show --predicate 'eventMessage contains "Previous shutdown cause"' --last 24h

Filtering the log data using "composedMessage CONTAINS "Previous shutdown cause""

Skipping info and debug messages, pass --info and/or --debug to include.

Timestamp            Thread   Type    Activity       PID  TTL

2020-04-21 20:43:00.030709+0800 0xb6    Default   0x0         0   0  kernel: (AppleSMC) Previous shutdown cause: -20

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Log   - Default:     1, Info:        0, Debug:       0, Error:     0, Fault:     0

Activity - Create:      0, Transition:     0, Actions:      0

What issue are you having ?

shaofeng0956 wrote:

mac book pro 13-inch 2018

mojave 10.14.1

Unexpected shutdown and restart

Use the above command to get the error code -20

The error code is undefined.

To get a good look at your System config. for conflicts or issues, you can download/run this trusted utility https://etrecheck.com  

If you need help interpreting the report you can post it here in its entirety in the "Additional Text" box in the editing toolbar below, in your reply.

You can set its preference to "Allow full Disk Access",  with this you get a digest of issues from the last 7 days that are saved in your system.  _No_ personal information is revealed.

See if you have a panic report (file's ending in .panic).  If you have more than 1, please post a couple as the differences can be very useful:

Look for the Kernel Panic reports at:

Finder -> Go -> Go to Folder -> /Library/Logs/DiagnosticReports 

<http://support.apple.com/kb/ht2546>

<http://support.apple.com/en-us/HT200553>

The panic report should have ".panic" in the file name.

You can put the panic report in an "Additional Text" box when you Reply