I cannot erase the files “install macos Catalina” “install macOs Mojave” and “install macOS High Sierra”

..yvesp..

Perhaps to try & use Safe mode on startup; then 'less system' is loaded

and you should be able to remove items in the Trash; then just restart.

Once the Mac has started in Safe mode, you shouldn't have to do more

than what you need. (Additional details in article, often aren't needed.)

• How to use Safe mode on your Mac - Apple Support

//support.apple.com/en-us/HT201262

[note 'Intel-based Mac' instructions]

There may be another means to remove those download/installers

from Trash.~ But this could be easier compared to understanding a

developer article from Apple support. However: there may be more

to the developer article, beyond just removal of items from Trash.

Actually disabling SIP is the only way to remove the files. It's not that complicated. It boils down to…

1. Boot into Recovery Mode
2. Disable SIP by running "csrutil disable" in the Terminal
3. Restart then delete the files
4. Then you should re-enable SIP by running “sudo csrutil clear” in the Terminal.

You need to temporarily disable SIP, delete the files, then re-enable SIP.

Disabling and Enabling System Integrity Protection

You're welcome.

To boot into Recovery Mode…

1. Restart your Mac.
2. Immediately press and hold Command-R: until you see the startup screen

Read my post.

Thank you for clarifying this with detailed response.

Looks more than adequate ~ even for non-techie!🥕🐇

Welcome.