Unofficial, unsupported troubleshooting page for Windows Vista 32-bit and Windows Vista 64-bit.

Getting ArmA to run properly on Vista

Install all updates available from Windows Update
Install DirectX9/10 Redistributable (Links: Guru3d)
Install one of the latest ATI or Nvidia drivers available (Links ATI NVIDIA Guru3d
Install Vista pre-sp1 hotfixes 940105, 936710, 936710, 938194 and 938979
Adjust ArmA shortcut to include -maxmem=512

Known Issues and Resolutions

Until either Bohemia Interactive, Microsoft or the Video Card producers come up with a solution, you can workaround this problem by limiting your System Memory to 3GB by a simple change of settings and a reboot:
- Press windowskey+R, and run msconfig
- At the boot tab, pick advanced options and put maximum memory to 3072
- Reboot
- You can also revert the setting by above method to get your full 4GB back
More methods might be listed soon, together with a method to get a selection screen at system boot up to pick "Normal Operation" and "Limited to 3GB"
More info on boot parameters available below, in the section Related Links

This is a problem confirmed with X-Fi cards and their drivers. Driver Release 2.15.0002 resolves this issue. Or you can add the startup parameter -dsound to ArmA Shortcut but other weird sound problems might arise in that case.

Make sure you have adjusted your startup shortcut to include -maxmem=512, in some cases it might be nececairy to tweak it further back. Try 384.