After talking to SAS Tech Support, it wasn't clear what precisely was causing the problem. But they did suggest dropping the autonumber field in the base ACCESS table since it was likely the root of the issue. I revised my code adding the underlined option and was able to append the data set. proc datasets library=pace nolist; append base=pace.tblLinkageLab (sasdatefmt=(date_import='mmddyy10.' labdate='mmddyy10.') drop=lab_id) data=check.case_check_labs force; run; quit; The appended rows were numbered in the lab_id field sequentially, but with a large gap between the last existing record's lab_id number and the first added record's lab_id number, but in this case that does not represent a serious problem.
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