I'm not sure when this started, but every so often I would periodically check to see if Marcus by Goldman Sachs would show up on the list of financial institutions when setting up transaction downloads. It showed up today, so I went through the steps to initiate transaction downloads and it worked. It is now using Plaid to link the bank to Quicken, so now I'm able to download all of my transactions again.
After the download and sync, I had to change my manually entered transactions, that were already in the register, from "Reconciled" to "Cleared" for the downloaded transactions to match so I wouldn't have duplicate entries in the register. The earliest ones were from back in February, 2026, around the time they stopped the transaction downloads before.
Just wanted to let everyone know.