Avast causing instant reboot

[KimTjik]

OS: XP SP2 Eng

As strange as it might sound the title is most likely correct. A time ago I started to get strange instant reboots (system instantly went into a reboot cycle without a proper shutdown). Of course I thought it could be caused by corrupted drivers, hardware not being stable, but after thorough testing of drivers (reinstalling and changing versions), stability and registry it all came down to Avast. Fortunately the system including all partitions are clean and going strong and look to be unaffected by these erratic reboots.

Every time I remove Avast the system worked perfectly well; notice this behaviour was isolated to the start-up procedure, if the system eventually got through it was solid as usually. I've tried older and newer versions and the issues are equal, except that without an updated database it somehow seems to not create trouble (but this could be a coincidence without value).

I've searched, but can't find any corresponding post, so I started this new topic. Have anyone experienced the same? Is there a known incompatibility with some other software which could cause this?

I will investigate further, but for now I run this system without any anti-virus program and let it boot and shutdown properly for awhile to avoid stressing the fragile Windows system more than necessary (doesn't really matter anyway, because this system is behind a separate good firewall and the mail are anyway checked by a separate server).

[igor]

Known incompatibilities... well, if you'd have another similar (e.g. antivirus) program installed, it may cause problems.
Otherwise, an active antivirus may stress the system a little more (by scanning the accessed files), so normally hidden hardware problems (memory errors, overheating CPU, ...) might get revealed.

Anyway, if your computer crashes, the corresponding minidump should be created in Windows/Minidump folder. Are there any recent files there?

[KimTjik]

No other active running anti-virus process is running. I got an idea which I will check: could "POP peeper" (E-mail notification) be interfering with Avast? In a couple of days I'll investigate it further.

Hardware stability? That's actually a part of my hobby and work, so I can for certain say it's stable (OCCT, Prime95 or its derivative Orthos, Memtest outside or inside a running operating system, 3D applications and so on). Temperatures of all sensors are well bellow any critical point; hard-drives don't show any signs of failure when tested. Since it's possible in some rare attempts to boot to completion with Avast installed, I ran a tuff test for the system while all background services were running, including Avast, and that doesn't affect stability at all. Therefore there must be some other explanation for these erratic reboots (without Avast installed the start-up procedure hasn't failed even once) which exclusively occur at start-up, never while the system is up running (therefore I can't say XP is crashing in the usual sense).

Anyway thanks for your suggestion. I'll keep testing and try to locate the actual reason.

[igor]

If you find the corresponding minidump files, we can investigate the reason of the crash.

[Lisandro]

Could "POP peeper" (E-mail notification) be interfering with Avast?

I don't think so... PopPeeper is running quietly in the system tray with avast and XP Pro SP2 here...
It is fully compatible with avast.