Thank you for that link. Using it to install Firebird 3.0 I got this result
installArchives() failed: Preconfiguring packages ...
Preconfiguring packages ...
Selecting previously unselected package firebird3.0-common-doc.
(Reading database ...
(Reading database ... 5%%
(Reading database ... 10%%
(Reading database ... 15%%
(Reading database ... 20%%
(Reading database ... 25%%
(Reading database ... 30%%
(Reading database ... 35%%
(Reading database ... 40%%
(Reading database ... 45%%
(Reading database ... 50%%
(Reading database ... 55%%
(Reading database ... 60%%
(Reading database ... 65%%
(Reading database ... 70%%
(Reading database ... 75%%
(Reading database ... 80%%
(Reading database ... 85%%
(Reading database ... 90%%
(Reading database ... 95%%
(Reading database ... 100%%
(Reading database ... 563724 files and directories currently installed.)
Preparing to unpack .../0-firebird3.0-common-doc_3.0.8.33535.ds4-1ubuntu2_all.deb ...
Unpacking firebird3.0-common-doc (3.0.8.33535.ds4-1ubuntu2) ...
Selecting previously unselected package firebird3.0-common.
Preparing to unpack .../1-firebird3.0-common_3.0.8.33535.ds4-1ubuntu2_all.deb ...
Unpacking firebird3.0-common (3.0.8.33535.ds4-1ubuntu2) ...
Selecting previously unselected package libfbclient2:amd64.
Preparing to unpack .../2-libfbclient2_3.0.8.33535.ds4-1ubuntu2_amd64.deb ...
Unpacking libfbclient2:amd64 (3.0.8.33535.ds4-1ubuntu2) ...
Selecting previously unselected package libib-util:amd64.
Preparing to unpack .../3-libib-util_3.0.8.33535.ds4-1ubuntu2_amd64.deb ...
Unpacking libib-util:amd64 (3.0.8.33535.ds4-1ubuntu2) ...
Selecting previously unselected package firebird3.0-server-core:amd64.
Preparing to unpack .../4-firebird3.0-server-core_3.0.8.33535.ds4-1ubuntu2_amd64.deb ...
Unpacking firebird3.0-server-core:amd64 (3.0.8.33535.ds4-1ubuntu2) ...
Selecting previously unselected package firebird3.0-utils.
Preparing to unpack .../5-firebird3.0-utils_3.0.8.33535.ds4-1ubuntu2_amd64.deb ...
Unpacking firebird3.0-utils (3.0.8.33535.ds4-1ubuntu2) ...
Selecting previously unselected package firebird3.0-server.
Preparing to unpack .../6-firebird3.0-server_3.0.8.33535.ds4-1ubuntu2_amd64.deb ...
Unpacking firebird3.0-server (3.0.8.33535.ds4-1ubuntu2) ...
Setting up firebird3.0-common-doc (3.0.8.33535.ds4-1ubuntu2) ...
Setting up firebird3.0-common (3.0.8.33535.ds4-1ubuntu2) ...
Setting up libib-util:amd64 (3.0.8.33535.ds4-1ubuntu2) ...
Setting up libfbclient2:amd64 (3.0.8.33535.ds4-1ubuntu2) ...
Setting up firebird3.0-utils (3.0.8.33535.ds4-1ubuntu2) ...
Setting up firebird3.0-server-core:amd64 (3.0.8.33535.ds4-1ubuntu2) ...
Setting up firebird3.0-server (3.0.8.33535.ds4-1ubuntu2) ...
adduser: The user `firebird' already exists, but is not a system user. Exiting.
dpkg: error processing package firebird3.0-server (--configure):
installed firebird3.0-server package post-installation script subprocess returned error exit status 1
Processing triggers for man-db (2.10.2-1) ...
Processing triggers for libc-bin (2.35-0ubuntu3.6) ...
Errors were encountered while processing:
firebird3.0-server
Setting up firebird3.0-server (3.0.8.33535.ds4-1ubuntu2) ...
adduser: The user `firebird' already exists, but is not a system user. Exiting.dpkg: error processing package firebird3.0-server (--configure):
installed firebird3.0-server package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
My guess is that I now have FB 5.0 going and so this installation of FB3.0 failed. I'll have a look.
Thanks for the link to the Linux Mint software site, which I will explore some more.
Thank you to everyone who contributed.
Regards
Nick