Crashing Realtek AC’97 ALCXWDM.SYS

Today I finally fixed a computer crash which was polluting my days for about 3 weeks now.
Earlier this month I bought a DVD burner to replace a defective old CD burner. The same day I rearranged my appartment in Strasbourg and installed large speakers. But as I rebooted my computer (…and Apache server) after the changes, it crashed shortly after login, then again. Initially suspecting the new burner, I disconnected it and regained a few minutes of stability. But something was still wrong and the computer was highly unstable, randomly crashing at any attempt to play sound or video. I suspected about every part of hardware, disconnecting piece-by-piece for testing, moving the ram chip of slot, running extensive ram tests, checking cooling, board, cpu and PC box temperature.
I then blamed it on the motherboard at its condensers were curved and leaking. I went on a hunt for a replacement board I couldn’t get. The EPOX K8RA2+ isn’t produced anylonger (bought in December ’03), nor available in stock of Strasbourg’s PC hardware reseller, nor at the shop in Karlsruhe were I initially bought the board ( – I have to salute the helpfulnes and promptitude of their feedback. I was anonymously tipped to go check ebay for a spare board, and while french ebay hadn’t any, the german one did had a single one which I ordered shortly after, paying an extra 17 euro for shipping to France as the seller confirmed he would ship to France. Since then, no news from the seller nor the shipment or board – I still have to request the reseller for a reimbursement and report a missing item.
Yet this morning I was fed up of the crashes and ran windbg to give it a look. – What an idiot I am, I should have done that at first instead of waisting time. I quickly found out that the same driver – alcxwdm.sys – was about in all the stack dumps, when the dump was not corrupted so much that the stack was not available at all (such as bad IP / Instruction Pointer).
See to find windbg. After install, go open the minidumps from C:\WINDOWS\Minidump type a .symfix and .reload in the prompt to setup the symbol path (Microsoft’s public symbol server), then a classic and powerful !analyze -v to get details about the dump – including the famous stack.
Googling ALCXWDM.SYS I quickly confirmed that it belonged to the installed to Realtek AC’97 audio driver, which makes sense since the crash occurred when sound was in use. I ran a custom windows update to see if the old driver was reported as subject a 3rd party update but no. I did although found an update for my integrated network chip which was in 2 of the 34 crashes thus installed it. Then I found an AC’97 update on the Realtek website ( – notice that search for AC’97 on their integrated search engine fails, what a shame). I installed this one, and rebooted.
Et voilà! No more crash. MP3s, Wishmaster Video clips, games are running again.
I’ll suggest Vince from Microsoft OCA to setup an answer for Realtek’s driver.
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