Can't remove "Install macOS High Sierra.app" I had to make a bootable macOS High siera install, everyhing went well and it worked. I'm trying to remove the app that I used to install it and trash won't let me. Everytime I try I get an 

The operation can’t be completed because the item 
“Install macOS High Sierra.app” is in use.


error. I tried to circumvent this by option+click and selecting "Delete immediately" but that just gives me an 

“InstallESD.dmg” can’t be modified or deleted because it’s required by macOS.


error. Any help for getting this thing off my computer will be greatly appreciated.
I was experiencing this problem after downloading High Sierra to fix a friend's Mac. I found Rick's solution worked for me, but I've added a few more steps.


Click the  symbol in the Menu bar.
Click Restart….
Hold down Command + R to boot into Recovery Mode.
Click Utilities.
Select Terminal.
Type csrutil disable. This will disable SIP.
Press Return or Enter on your keyboard.
Click the  symbol in the Menu bar.
Click Restart….


Extra Steps


Log in / boot up the Mac.
Empty Trash.


I also found that somehow Previous System folder appeared under the Mac HD. So I also trashed that (which wouldn't trash previously).

I then rebooted the Mac a few times to check that everything was working fine. Then rebooted into recovery mode.


Hold down Command + R to reboot into Recovery Mode.
Click Utilities.
Select Terminal.
Type csrutil enable. This will enable SIP.
Press Return or Enter on your keyboard.
Click the  symbol in the Menu bar.
Click Restart….