| .accde |
Access Execute Only Database |
| .accdr |
Access Runtime Application |
| .accda |
Access Add-in File |
| .accdc |
Microsoft Access Signed Package |
| .alc |
Ableton Live Clip File |
| .acf |
Steam Application Cache File |
| .aml |
ACPI Machine Language File |
| .aoi |
Art of Illusion 3D Scene |
| .accft |
Microsoft Access Data Type Template |
| .avhd |
Hyper-V SnapShot File |
| .appx |
Windows 8 App Package |
| .appxupload |
Windows 8 App Upload Package |
| .accountpicture-ms |
Windows 8 Account Picture File |
| .acg |
Audio Comparer Group File |
| .age3xsav |
Age of Empires 3: The WarChiefs Save File |
| .age3ysav |
Age of Empires 3: The Asian Dynasties Save File |
| .age3rec |
Age of Empires 3 Recording |
| .age3xrec |
Age of Empires 3: The WarChiefs Recording |
| .age3yrec |
Age of Empires 3: The Asian Dynasties Recording |
| .arn |
Autoruns Data File |
| .avhdx |
Automatic Virtual Hard Drive File |
| .atomsvc |
Atom Service Document |
| .aca |
Agent Character Animation File |
| .ate |
Office Accounting Compressed Backup File |