verified workaround incident #919957, Margaret Maher, on Windows 7 64-bitAML performance on that config is 50% slower than on 32-bit machine running same code.Workaround: at the DOS prompt enter "%windir%\SysWoW64\cmd.exe", then start Arc:. That puts the session in 32-bit mode, and performance is the same as on a 32-bit machine.==================KB34330------------In the Windows Task Manager > Processes tab, set Priority for arc.exe to High (ref. inc. #730226).9-7-10 Margaret Maher, ref. inc.#845753The problem was resolved by turning off virus scanning software on the computer while the AML code was running. The source of the problem was concurrent access to scratch files created by ArcEdit by the virus scanning software, while ArcEdit was attempting to delete the files at the close of the ArcEdit session.