Is it possible to have a hyperlink in the custom field? Specially, if I could get it to show on the Quick Launch screen, that would be great.
The custom field is a 100 character text field - so yes you can store a URL, UNC path etc. in there as long as 100 chars or less, however, it will not become "clickable" within Kaseya, as Kaseya will simply display it on the screen as text and not surround it by the HTML code that would make it a "link". You can always copy and paste the link text to a new browser tab, however.
So, in short, no you can't do that.
You can put custom static links into live connect under system->live connect->custom links and create a new home page to put the links into; you can then assign these links on a machine role or VSA user role basis. The links are all static entries, however - you can't query agents and build links dynamically.
I f anyone else is looking to do this, the Chrome plugin "Text URL Linker" does the trick. It even works in the quick launch window.
You can install it right from the store! You don't even need to install 7-zip, extract the plugin, put the browser in developer mode, manually install the plugin and click a prompt every time you open the browser ;)