Thanks @rajssai. A few comments with those in mind who may encounter a similar issue in the future.
I’d discourage using killall -u $(whoami) in this context, as the command may terminate jobs unrelated to cryosparc and may not terminate relevant cryosparc processes, depending on how the computer and cryosparc are configured. Termination of relevant processes is discussed in another thread.
Only after ensuring that all relevant processes have in fact be terminated
(ps -eopid,cmd | grep 'cryosparc\|mongo' is your friend), check for and, if necessary, remove leftover /tmp/mongodb-*.sock and /tmp/cryosparc-supervisor-*.sock that belonged to the cryosparc process just terminated. Be careful, problems may arise if lock files belonging to an active cryosparc instance are removed.
After the relevant old processes and lock files are gone, try restarting your cryosparc instance using cryosparcm start or systemd, as appropriate given your cryosparc setup.
If the attempted cryosparc startup fails, you may need to repair the database as discussed on the forum. If you are unsure about the underlying cause of the failure, please ask for help on this forum.
[Edited 2022-03-23 to include ‘mongo’ in grep filter]