Troubleshooting Tip: How to identify FortiClient EMS upgrade fails due to the/tmp folder not having enough free disk space

When check EMS installation log, the following output shows the error message:

Read: 13.5 GiB ==> 82%zstd: error 70 : Write error : cannot write block : No space left on device
dpkg: error processing archive /tmp/apt-dpkg-install-ohP46o/7-forticlientems_7.4.5.2111.M_amd64.deb (--unpack):
new forticlientems package pre-installation script subprocess returned error exit status 1
/*stdin*\ : Read error (39) : premature end
tar: Error is not recoverable: exiting now
dpkg: error while cleaning up:

The keyword 'premature end' means the installation has not even started yet. 

It is recommended to have /tmp 1.5 times free disk space larger than /opt/forticlientems.

To check the current free disk space of both partitions, the following commands can be used.

du -hs /opt/forticlientems

df -h /tmp

Related article: 

Technical Tip: How to expand disk space in FortiClient EMS v7.4.x