An alternative message you might get from ":query" option is this:


I'm assuming it would be potentially harmful to performance to switch on compactos if this message comes up.

DavidY said:

I'm assuming it would be potentially harmful to performance to switch on compactos if this message comes up.

Maybe, maybe not. When I upgraded my OS was compacted, when I clean installed on same hardware it wasn't. I did an in-place upgrade and it was again.... The exact conditions that the system uses to decide aren't documented that I can see - some combination of RAM/CPU/Free Space/Disk

You can always try it and turn it off again if it is slower. It may even be faster (slow disk, fast CPU for example) - it depends on your specific set-up..

halasz said:

Maybe, maybe not. When I upgraded my OS was compacted, when I clean installed on same hardware it wasn't. I did an in-place upgrade and it was again.... The exact conditions that the system uses to decide aren't documented that I can see - some combination of RAM/CPU/Free Space/Disk

Actually I had the same - I have a tablet which was running 8.1, and when I upgraded, CompactOS was on, but after a clean-install it wasn't.

In my case I'm assuming it was because the clean-install didn't have the right drivers (I had to add some manually), and my best guess was that the disk didn't look like a solid-state device and that tipped the balance so it decided not to compact.

DavidY said:

In my case I'm assuming it was because the clean-install didn't have the right drivers (I had to add some manually)

It could be drivers - I had to add some also - I just assumed free space. Really I don't know though.

If your interested in saving more space I've also compacted these directories with compact /c /s /a /f /q /i /exe:xpress16k ... I've not seen any performance difference but it saves a lot of space, especially if you have Office...

Most other big directories I've tried seem to stop Windows booting or otherwise behave badly (programdata, appdata, system32\driverstore\filerepository for example) but these work OK.

Code:

$env:programFiles
$env:programFiles(x86)
$env:homeDrive\MSOCache
$env:homeDrive$env:homePath\Documents
$env:windir\Assembly
$env:windir\InfusedApps
$env:windir\Installer
$env:windir\Panther
$env:windir\SoftwareDistribution
$env:windir\System32\Catroot2
$env:windir\System32\LogFiles

Thank you for this post ! I decided to try out a super cheap laptop with only 32GB as a travel device. Bad idea. mostly because Windows 10 really needs a 64GB drive if you want to install some standard apps and still have enough room for performance. That said, this device came with the OS compacted. I decided to turn that off and see what the performance is like since task manager showed compression as a major resource sucked. Long story short, uncompressing only cost me 1GB is space. Before that Windows 10 was using 10GB of space. So the net gain on compression was only 10%, not at all worth it. Personally, I would keep the OS uncompressed.

MrBill said:

I decided to turn that off and see what the performance is like since task manager showed compression as a major resource sucked.

Did you find any performance difference? In my testing I've found uncompressed to be the slowest even if you have SSD (not that it would always be the case). See this thread for example Any useful scenario for NTFS compression? - Page 2 - Windows 10 Forums

lx07 said:

It could be drivers - I had to add some also - I just assumed free space. Really I don't know though.

If your interested in saving more space I've also compacted these directories with compact /c /s /a /f /q /i /exe:xpress16k ... I've not seen any performance difference but it saves a lot of space, especially if you have Office...

Most other big directories I've tried seem to stop Windows booting or otherwise behave badly (programdata, appdata, system32\driverstore\filerepository for example) but these work OK.

Code:

$env:programFiles
$env:programFiles(x86)
$env:homeDrive\MSOCache
$env:homeDrive$env:homePath\Documents
$env:windir\Assembly
$env:windir\InfusedApps
$env:windir\Installer
$env:windir\Panther
$env:windir\SoftwareDistribution
$env:windir\System32\Catroot2
$env:windir\System32\LogFiles

Can someone post what the compact switches do that are listed in this post?