flashing exclamation point on agent icon in sys tray - what does this mean
If it's the kaseya agent flashing - click it. It'll display a message to the user (usually notifying them that an update has occurred). The agent basically flashes whenever it has a message for the user. help.kaseya.com/.../index.htm
If it's 'some other app' - well it could be almost anything (e.g. apps bundled with the machine, OEM app, virus/malware, etc) . Try left and right-clicking it to find out what it is and what it wants.