SOUND ON SOUND

[Gone To Lunch]

My Mac Pro, High Sierra 10.13.6 is booting slower and slower, first attempt this morning, after about 15min, of extremely slow status bar below the apple logo, I re-started via the power button and it was quite a bit quicker, but much slower than it has been ordinarily.

What might this be, and how might I fix it ?

[desmond]

Drive problems? Hardware problems?

Do a disk check using disk utility...

[Gone To Lunch]

Well, I closed down and then re-started, and the problem went away.

So that's that.

For now.

[Gone To Lunch]

Problem is back again.

Ever slower status bar under the apple log when I boot.

[desmond]

Problem is back again.
Ever slower status bar under the apple log when I boot.

Every time, or just once? What happened when you tried the suggestions I already made above?

[fruitcake]

Check your console logs. Also try starting up in verbose mode. It can help tell where the boot up is hanging.

[Gone To Lunch]

Problem is back again.
Ever slower status bar under the apple log when I boot.

Every time, or just once? What happened when you tried the suggestions I already made above?

My mac is bootable from two drives, System with 10.11.3, and Projects with 10.13.6 so I re-selected the boot drive from my preferences and that seemed to cure it for a while.

I have since booted from Projects so as to run the disk repair utility on System and that helped for a couple of boots, but it is now back again when I boot from the preferred System drive.

I have tried safe booting, and that stops it.

[MOF]

Did you try First Aid in Disk Utility also is there at least 10% spare capacity on your boot drive?

[Kwackman]

I have tried safe booting, and that stops it.

Consistently?

[Gone To Lunch]

Did you try First Aid in Disk Utility also is there at least 10% spare capacity on your boot drive?

Yes, and there is 50% spare capacity on that drive

[Gone To Lunch]

I have tried safe booting, and that stops it.

Consistently?

Don't know, I only did it once, and running the repair utility seems to have done the trick.

And I also re-selected the drive from within the system preferences and that seems to clear it as well.

[Gone To Lunch]

It happened again so this time I emptied the cache - for the first time - I have this mac for 3 years - and that got it back to normal.

[MOF]

It happened again so this time I emptied the cache - for the first time - I have this mac for 3 years - and that got it back to normal.

Which cache?

[Gone To Lunch]

It happened again so this time I emptied the cache - for the first time - I have this mac for 3 years - and that got it back to normal.

Which cache?

Open Finder, select “Go”, click “Go to folder”, type “Library/Caches/”, delete all files, and empty trash.

[MOF]

Open Finder, select “Go”, click “Go to folder”, type “Library/Caches/”, delete all files, and empty trash.

OK thanks, that sounds pretty comprehensive, I hope you didn’t throw some babies out with the bath water.

[cyrano.mac]

It happened again so this time I emptied the cache - for the first time - I have this mac for 3 years - and that got it back to normal.

Which cache?

Open Finder, select “Go”, click “Go to folder”, type “Library/Caches/”, delete all files, and empty trash.

You might want to do a restart, right after deleting the caches, to give the system the opportunity to rebuild them. You'll notice the first restart taking a little longer.

Subsequent restarts should be back to normal speed.

[Gone To Lunch]

Subsequent restarts should be back to normal speed.

Indeed they are.

[Eddy Deegan]

It happened again so this time I emptied the cache - for the first time - I have this mac for 3 years - and that got it back to normal.

There is a bit of an irony there. Caches are obviously intended to enhance performance, and mos of the time they do, but when emptying a cache improves matters you know that someone, somwhere got something somewhat wrong.

It's attention to detail on that level that Steve Jobs was good at. Even though he didn't have much idea of how it worked under the hood he was a wizard at spotting and having someone fix things like this.

Not that it's easy to fix. To cite a quote that's been round for a few years now:
There are only two hard things in Computer Science: cache invalidation and naming things.

Glad it's working better for you now :thumbup:

[cyrano.mac]

Speed isn't the obvious reason to have caches on macOS...

Reliability is. The way macOS is installed, the original binaries are only loaded and copied once, to the cache. From the second boot, the system starts from the cache. But it's on the same disk, so speed is about the same as a system without a cache.

If for whatever reason, binaries in the cache become corrupted, the system will replace them by making a new copy from the original.

MacOS also installs a lot of binaries that aren't needed for a particular configuration. These don't get copied to the cache. If the user connects something new later on, the needed binary will be added to the cache.

And /tmp isn't even the location of the cache itself. It does contain the config files for launchd. And these contain the list of files to load.

If you really want to delete all caches, you can use the Terminal, or a utility like Nothern' Softworks Cache Cleaner, or Onyx.