I stay in NYC every week - 3 nights - Marriott East Side - and made Platnium - I have verbal confirmation but still my online status is not updated as I want notify United Airlines to boost me to silver as I fly that nightmare every week.
How long does it take to get formal notification?
Platinum should register as soon as the latest stay credits, since that will take your night count to 75, triggering Platinum. Of course sometimes the nights can credit within a day or two, other times can be a wait of a week. Until it credits Marriott.com won't show you as Plat and you won't be acknowledged as United Silver either.
You could chase it up with the elite line to try and get the stay to credit faster, but that's about it...
First, welcome to the Insiders forum cstys
As you have taken the time to do so here, the Insiders network is the perfect place to introduce content like you have done here, and seek insight from a large group of well traveled and knowledgeable individuals that are always willing to help out a fellow traveler!
While you explore the page and interact with some of the people who've responded to you post (way to go bejacob and brightlybob, as usual!) I encourage you to check out our Getting Started Guide for tips and tricks on how to best navigate the site. Also, don't hesitate to reach out to me (joshm), lindseyh, or CariJ with any questions about the site or anything Marriott Rewards. We make up the moderation team for this site and we're here to help!
Regarding your post, and as bejacob recommends, giving the customer care team a call should do the trick to get your status updated. If you would any further assistance, don't hesitate to shoot me a DM with your Rewards # and contact info. I'd be happy to provide support.
Welcome to the forum.