macOS 10.14.5 random system freeze

I just wanted to provide an update about the situation on my end (I'm not OP btw);

I tried multiple things in order to figure out the cause of this freezing issue:

1) Reinstalling macOS without erasing the SSD (Didn't work, still had freezes)

2) Booting from an external drive with the latest (10.14.5) macOS installed, and using it for a few hours without any third party apps installed. (Still froze)

3) Finally, I couldn't take it anymore and decided to create a usb installer for macOS 10.14.4 and it successfully installed without the need to erase my SSD. All my data is still here, and I haven't had any freezes since.

Please determine if the same problems occur in "Safe Mode": Use safe mode to isolate issues with your Mac.

Wish I could downgrade my Mac to the previous macOS version.

What is preventing you from doing that?

I updated to 10.14.5 thinking that by revision 5 they would have worked the bugs out. Um... NO. The os became unusable right after the upgrade.

The ONLY fix I found to make my machine useable again was to disable EVER DRIVE I use on my machine in Spotlight search.

Mind you, unchecking ALL the boxes in Spotlight Search will NOT do the trick, you have to go to the next tab [Privacy] and drag EVERY Hard Drive on your mac into that box. That will PREVENT Spotlight from searching anything on those drives.

You know, that part of the os that is constantly sifting through the DATA WITHIN your documents to allow you search the contents of your files without bothering to remember what you named them. I have always found this function at best useless and at worst invasive. To reaffirm this workaround, I forgot to disallow Spotlight from scanning a new drive I got from work with Photography work on it and shortly after working on the drive, I AGAIN got the beach ball of doom. To be clear this did not solve EVERY instance of this weird lock up, but most of them. Enough for me to actually get work done again. I also suspect laggy internet connectivity may also initiate this weird lockup. The only thing out of the 'ordinary' when I updated was that I jumped one or two OSs when I upgraded. Oh I also manually shut off every single application from using iCloud because I don't like iCloud. Not for security reasons (Im sure its fine for that), I don't like it because It wastes MY TIME doing things that don't serve ME....

Hope this helps.

Spoke to Apple Support online, they suggested SCM https://support.apple.com/en-au/HT201295 and NVRAM reset https://support.apple.com/en-au/HT204063 (as usual) as well as having at least 15% free disk space. 

https://support.apple.com/en-au/HT206996 | https://www.cleverfiles.com/howto/best-disk-space-analyzer-mac.html

I have a 500GB usable (512GB) drive, so that means having at least 75GB free, usually it has been 26GB free lately, dipping to 6GB during heavy Chrome swap memory usage. Could be the reason for the freezes but we'll have to wait and see. I found 246GB of old holiday photos that I tried exporting to my Synology NAS last year, but Finder always failed with transfers that large so now I'm transferring month by month only. Seems to be working at around 5MB/s over 5GHz Wi-Fi AC. :D  

Also a point to note: file deletes on the origin only happen once the entire move for all files has completed, i.e. it's not an atomic transaction.

I understand Safe Mode can be impractical with intermittent or sporadic problems.

You can restore a previous macOS version with Time Machine. Whenever you install a macOS update, Time Machine creates a “local snapshot” of the existing system that can be restored in the event something goes wrong, or if you want to “undo” the update for whatever reason. I’m not using a Mac at the moment but I can provide step by step instructions later, should you need them.

It goes without saying though that scam “cleaning” apps are capable of wreaking such havoc that the only practicable way of recovering from the effects of having used them is to completely erase those affected Macs. Often those effects don’t become evident until after a macOS update or upgrade. It’s an extreme solution that is not quite yet justified.

Nearly two decades after its inception users continue to insist on installing garbage products that prevent macOS from working properly. "Avast" is among the worst offenders. Ironically, its uninstaller is a model of perfection. Use it.

You can restore the previous system with Time Machine. I am not completely certain enabling TM is even a requirement though, since it is enabled on all my Macs. None have ever been affected by "Avast" or its ilk though.

1. Boot macOS Recovery.
2. At the Mac OS Utilities screen, select "Restore From Time Machine Backup" > Continue. A Restore from Time Machine screen will appear. Read it then Continue.
3. When the Select a Restore Source screen appears, select the internal disk. Its default name is "Macintosh HD" but you may have changed it. Continue.
4. The Select a Local Snapshot screen appears next. Restore From > Local Snapshots on Macintosh HD (or whatever you named its startup disk) will appear in the dropdown menu selection.
5. If a Local Snapshot Date & Time list populates, select one that corresponds to the version you want to restore. Continue.
6. A confirmation dialog will appear. Read it then Continue.
7. A Restoring screen will appear next. That operation won't take long.
8. A Success screen will appear next, and the Mac will restart.

Cleanmymac is one of the worst enemies of a healthy mac.

Even after uninstalling, there is no way to tell what damage it has left behind.

I recommend you do a full backup (preferably two).

Erase and install a fresh copy. Migrate only the user accounts (NOT applications, settings or other files - you don't want to migrate the problems back!)

If you want, before you do a clean install you can try running the Combo Update over the present system. Sometimes this fixes files that were corrupted or deleted, but with cmm...

Try uninstalling Avast. It is most likely what is causing the freeze...

macOS has its own system protection and third party antivirus are known to cause more issues than they solve (which is basically none).

Follow this guide on how to create a usb installer: https://support.apple.com/en-us/HT201372

As for getting the older macOS version you wish to install... Apple no longer hosts a download for it, so you'll have to get it from somewhere else. It is still possible to find online, you just have to dig a little.

How are you able to get the version 10.14.0? I was told by a senior apple tech that the only way to get that version is if an apple store has a network drive containing that version, since the App Store only has Mojave 10.14.5. There’s no way to get Mojave’s 10.14.0 then use the combo update to get to 10.14.4

To get around the freezing I just installed the OS that came with my MacBook then upgraded to High Sierra.

You can check to see if you've removed all of the files by downloading and running the free version of Find Any File to search for any files with the application's name  and the developer's name in the file name.  For example for CleanMyMac you'd do two searches:

1 - Name contains cleanmymac

2 - Name contains macpaw

Any files that are found can be dragged from the search results window to the Desktop or Trash Bin for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.