Clean install of macOS and databases

When Sonoma is released, I’m going to do a clean install on my Mac. When I reinstall DT, should I use my saved database files, or restore from the backups? Is one better than the other for this purpose?

You haven’t provided any details on your backups
I use the Arq service; which holds the database contents in incremental components
In theory, this will restore the database however I’d feel safer using a saved copy

My third option is to restore using the sync datastore from the cloud

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You can pull them from your backups. However, if it were me I would run a last File > Verify & Repair Database on each database, then copy to an external drive:

  • The databases
  • ~/Library/Application Support/DEVONthink 3 directory
  • ~/Library/Preferences/com.devon-technologies.think3.plist

Then I’d copy them from that drive post-OS install.


These instructions for doing a fresh install are very good. To me it makes more sense to manually save and transfer your databases rather than restore from backup (although that might just be some old thinking from when you literally did just transfer files to a new computer!).

Setting up DT itself doesn’t take particularly long, but just so you go into this with eyes open in case you’ve not done it before: you’re looking at at least 6 hours of work doing a fresh install. OS Ventura took 2 hours to install when I did a fresh install recently (you can leave it to run by itself), and it then took several hours to install my essential apps and get things set up back how I liked it (I still haven’t installed “lesser” apps - mostly I am just doing it as a need comes up, so technically my work isn’t finished, though it hasn’t bothered me).

Also, documenting this for anyone who needs it: you need to use Disk Utility to erase the Mac if you want to do a clean install. Do not use the “Erase all content and settings” option in Settings/Preferences if you want to do a clean install. (Source = Apple Support)

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Perfect thank you so much. I do a Verify & Repair, and save an archive to an external drive, once a month. I’ll just save the actual database.

With every new OS, I do a clean install. I have always made a bootable USB stick, and formatted from the prompt.

It actually takes me days, because I have to download so much content (apps, files, etc) and my internet is under a 10mb connection. Dismal.

What’s the benefit of this approach?

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You’re welcome :slight_smile:
A reformat and reinstall is time-consuming but I too love the effects :smiling_face:

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It started as a hold over from my Windows days, but I find my Macs too, perform much better with a clean install of each OS.
Especially when the change is significant.

It gets rid of apps you’re no longer using, and cleans up all the stray bits left behind. I’m not a brilliant techie, I just know enough to make my system run smooth and not break anything :slight_smile:


I do the same for mostly the same reasons.
This is my anecdotal experience but I’ve helped many friends and colleagues get a few more years out of aging computers by cloning their system drive, (or straight out replacing it) and then installing a clean OS on an empty drive.
For my own purposes I use the clone to copy the Documents, Downloads, Dropbox, GDrive, OneDrive folder back on to the new drive and then refer to the clone drive for the priority list of Apps to install on the new system. Carbon Copy Cloner is always one of the first things I install.


I don’t think that removing stuff from the disk makes anything faster. The days of defragmentation are long over…
But if you have the feeling that everything is faster – go for it.

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It is not only fragmentation. There are a lot of other things, like old not needed drivers that load and then use memory and CPU, same for configuration files, startup programs not installed anymore that try to start… And with SSD drivers, the TRIM command. When you format a SSD disk, it emits an “all sectors TRIM command”, resetting all cells to non-written status, that has the advantage of checking those cells as well. A just formatted SSD performs waaaaay faster than one with a lot of writes (and yes, the TRIM command is executed on normal sanity checks, but not always all cells are deleted because no IDLE times or simply driver errors, eg, some disks that has 4/8/16-blocks as one sector, only TRIM first block but not the n remaining, dramatically slowing future writes…

Said that, I don’t reinstall if I’m not forced to. Not macOS and not even Windows since Windows 10.

A thing against full reinstall today is both macOS and Windows have “inmutable” system installations that are exceedingly difficult they can corrupt. Normally, creating a new user and deleting the old one is enough (passing through an intermediate one).


Good point, thanks. Though … if they’re Apple drivers, they’ll be replaced by new ones. If they’re not from Apple, they’re either needed and loaded of the hardware is present. Or the hardware is not present, than they shouldn’t be loaded. I think. With modern machines, the TRIM command might bring a real advantage.

While I was using Linux, I never did a complete new installation. Just compiled the kernel and that was that – never noticed performance problems. But that was well before SSDs became a common thing.

That is the reason I don’t install from if I’m not forced to. I don’t see much performance difference between reinstall without formatting, user account regeneration or simply update.

When I see some improvements, that last only a couple of days, it is an installation with full disk format, and I think it is not worth to because after two weeks, my system will work as fast (or as slow) as previously.

For example, I only reinstalled my MBP 16" M1 Pro one time, and I had to do that because, well, I started messing with the partitioning and ended in a non-bootable system, and my mini M2 Pro never had a reinstall (well, it is not much old, but haven’t yet and I think never will).

However, my iMac 2017 had zillions of installations due to problems with fusion drives, but after I put a full SSD, only reinstallations came because I put Windows and/or Linux and wanted to start over.