Supplemental Schedule E
Found at:
Had the original poster bothered looking at the foot of the Schedule E report, he would have seen a blue link labelled "Resolve Unspecified Rental Property Expense transactions ....".
Clicking that blue link would have presented a Quicken Help window that begins with the text, "This procedure explains how to resolve unspecified rental transactions from any report where they appear ....". Then clicking on "How do I resolve a transaction" would have provided all the causes (and fixes) for "unspecified rental property transactions".
Alternatively, had the original poster gone to Help > Search Quicken Help and keyed "unspecified expense" in the Search box, then clicked iSEEK (or pressed Enter); then, in the resulting Help dialog, clicked the arrowhead alongside the text "How do I resolve this?", the poster would have gotten the same assistance as noted above.
[Pretty much the same alternatives exist for "unspecified" business expenses.]