Notes about the ACH file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The ACH file type is primarily associated with 'Medlin Accounting' by Medlin Accounting. (Some banks call this the "NACH" or "NACHA" format.) Many banks can use the file, to initiate automatic deposits of net payroll to participating employee’s bank accounts.