I'm running into this same issue on Linux, and clearing out /usr/local/harris/license/flexera-sv/ and /tmp/Harris does *not* make a difference.

I was looking for an answer for the same question - upgrading my compute machines from CentOS7 to Ubuntu 20.04, and suddenly only one IDL user per machine.

I tracked the problem down to the following.

- on start, the IDL binary uses the licence library to create some files in /tmp, specifically one called /tmp/fne.[long string of apparently random characters] - this is a zero byte file, owned by the person running IDL. It's not deleted on exit.
- The next person who tries to run IDL will try to write to the same file name, and fail, despite the file being configured with 0777 permissions.

On CentOS, 0777 allows any user to open the file with write permissions, but newer distros - which use systems 241 and later, implement a new security protocol added in kernel 4.19 where even with 0777 permissions the file cannot be written to by anyone other than the owner. This is the new fs.protected_regular sysctl.

See:

https://www.spinics.net/lists/fedora-devel/msg252452.html
https://unix.stackexchange.com/questions/503111/group-permissions-for-root-not-working-in-tmp

Ubuntu defaults to a non-zero (2) value of fs.protected_regular. If one resets it to zero:

sudo sysctl fs.protected_regular=0

then anyone can write to a 0777 file, and multiple users can run IDL on the same system once more.

Obviously this is not great in terms of security but maybe Harris will update the license manager code if enough people complain.

I've been dealing with IDL for over 20 years. lmgrd is always pain. Hopefully this will help someone else with the same problem.