This is not the best practice in my own opinion.
Putting HIPS on Trainning mode while disabling auto-sandbox at the same time is not safe.
Adding vendors manually is not convenient.
In fact, we just need to keep HIPS and auto-sandbox enabled.
At the same time, keep the cloud lookup enabled.
Then, we just need to double click the applications whose vendors are reliable.
When these executables are identified as safe by the cloud of comodo, their vendors will be added to the trusted vendor list automatically.
For tightest security, Comodo recommends removal of all unneeded vendors from Trusted Vendors List.
@Umbra is just indicating a convenient way of doing it... as opposed to long, drawn out manual method of going down the File List and deleting entries.
The method he used is perfectly safe on clean system, but I would keep auto-sandbox enabled.
Comodo Cloud will protect physical system with active Training Mode.
With Comodo Cloud and auto-sandbox enabled, any Unrecognized files will be auto-sandboxed. At the same timeTraining Mode will create HIPS rules for any sandboxed Unrecognized files. In other words, the physical system is protected from persistent infection. If the Unrecognized app is determined to be unsafe\malicious\suspicious then the user simply has to delete the auto-learn HIPS rules.
FYI - I am not sure what is up with Trusted Vendor List updates. Vendors are added to TVL by Comodo techs, but the vendor never gets added to the users local TVL. Newly added vendors are supposed to be updated during signature updates on a user's local CIS installation - I believe. Not sure if it is bug or issue with Comodo infrastructure. There have been complaints about it for a while now...