I'm starting a master's program in London in September, and basically, I'm wondering how long it takes for a CAS to be issued. I can't seem to find a good answer for that. I'm having a hell of a time trying to get any answers from my school's international office, and I have some reason to believe there may be something weird going on (was mistakenly sent a weird email in the beginning of July asking if I'd be attending when I had already accepted my offer--last I heard (nearly a month ago) they were checking with finance that I'd paid the deposit and then my file would be ready for a CAS, international office has been annoyingly unresponsive to emails).
The CAS cannot be issued more than 6 months before the course starts and most universities will issue them in June or July for courses starting in September/October.
However, they cannot issue it until they have all of the information from you, such as transcripts, financial evidence etc., so if they are still waiting on confirmation of your financial deposit, then there's nothing you can do but wait.
I seem to remember someone here on the forum a year or two ago who was waiting and waiting for her CAS, wondering why the university hadn't issued it yet, when it turned out she hadn't paid a mandatory deposit to the university yet, and they were waiting for her to pay it before they could issue the CAS.
I would keep trying to contact the international office until they can give you the information about your CAS.
Unrelated, but I'm here so I may as well ask anyway: when applying for the tier 4 student visa, do I need to send school transcripts? I have a BA and an MS and I'm not sure if I'd need to send one/both (UKBA site confused me, saying US residents backed by a "highly trusted sponsor" are exempt from a lot of these sorts of things?)--or is this all something that would be on my CAS?
As you are from a 'low-risk' country (the US), then you don't actually have to send all of the usual required documents (
http://www.ukba.homeoffice.gov.uk/visas-immigration/studying/adult-students/evidence/).
However, UKBA reserves the right to request that you provide them if they so wish, so I would make sure you have all of the required documents available - transcripts, financial evidence, etc. - even if you don't actually send them with your application.
Here is a list of the supporting documents for a Tier 4 visa:
http://www.ukba.homeoffice.gov.uk/sitecontent/documents/out-of-country/documents-t4-gen.pdf
