If you get an error in the log that looks like this:
Exception thrown storing stream in new SqlRemoteBlob: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> Microsoft.Data.SqlRemoteBlobs.BlobStoreException: There was a generic database error. For more information, see the included exception. —> System.Data.SqlClient.SqlException: Invalid format specification: ‘%hs does not exist.)’ while attempting ‘NtCreateFile’ on ‘D:\SQLRBSWSS_Content13bc3f57-1564-4b1d-98db-dc6008bd7d2366c4d9d9-94d2-4e91-9495-4ac5d4898801000031a-000018f4-0012
Check to make sure the destination folders exist. Mine did not.
My RBS works fine for my root site collection, but I got errors when uploading larger files within a non-root site collection.
I’m suspecting that the RBS Provider (or whatever actually creates the folder structure) didn’t create the necessary subfolders when I created the non-root site collections.
Once I manually created the folders, I was able to upload larger files with no issues.