FuzzyDupes requires quite a lot of memory to do the duplicate search. The maximum size of the the data that can be searched is limited by the free memory available. A 32-bit system can have a maximum of approximately 2.5 GB of memory to be addressed, even if more physical RAM has been installed. FuzzyDupes 5 was successfully tested with up to 1.5 million data records. This value can fluctuate and depends on free memory, the number of columns and the redundancies in the data. Please close other applications that require a lot of memory. Create a new query in your database that returns only the relevant columns. If this still is not enough, you can pre-select and break your data into smaller chunks according to a specific criteria (eg 1st digit of the ZIP code). In addition to the 32-bit version a more powerful 64-bit Parallel Edition is now available.