I had forgotten Microsoft Access is a memory hog. Through VBA, I was trying to load 29 files into Monarch to export to a database. Most of the files are only one or two pages long, but some are 50+ pages.
My routine got as far as reading the 6th file (87pp) and it stopped. I looked at my memory usage and it was at 100%, with Access being the first app and Monarch being the 3rd.
My only workaround for this was to load and process each file individually rather than as a group.
I hope this serves as a tip to others.