Causeway Errors -- What Are They and What Can Be Done About Them?

Donald Kenney (
Last Update: Mon Jan 11 10:19:23 2016


I Recently had some problems with a bad memory module in one of my Windows PCs. One of the symptoms was a program -- I forget which -- reporting "CAUSEWAY ERRORs" during Windows initialization. A bit of Googling revealed that CAUSEWAY ERRORs are reported from time to time from some MSDOS programs including GHOST, AVG Anti-virus, and others that I have never heard of. What I didn't find easily was any clear explanation of what CAUSEWAY is or why these errors turn up. There is a general tone of exasperation/puzzlement/frustration in the messages posted by those who encounter these messages.


It turns out that Causeway is a memory manager a.k.a. -- A DOS extender. Memory managers make the large amounts of memory available on PCs in the last decade available to MSDOS programs. Causeway is the memory manager that the Watcom C Compiler will link programs to when they are compiled. There is a fairly decent manual for CAUSEWAY at Memory managers control the usage of memory beyond the 640K that was available on the 8086 CPU that was used in the original PC. Popular memory managers include Causeway, DGJPP, and DOS4GW. Almost all PCs with a 386 or later CPU will use memory managers to run larger programs. See for more information on memory managers.

See also

There is a list of causeway error codes at

In some cases an error file -- likely called CW.ERR may be written.

Error messages from Causeway often seem to report an Intel exception code 0-12 hex (e.g. 0C is a Stack Fault) instead of or as well as a Causeway error code.

I found one claim -- that might be true -- that even numbered errors relate to misbehavior by the object program

Here's a list of programs that seem to have reported CAUSEWAY errors at various times:

What causes CAUSEWAY errors?

So far, I haven't found much in the way of in depth analysis. My problem was caused by a faulty memory module and that seems to be a frequent cause. Others report the problems go away sometimes when disk images are replaced with new copies, so perhaps corrupt binaries are a problem. Many problems seem to be associated with Windows 2000, but I can't see any solid evidence of a bug or incompatibility. Causeway errors could presumably be caused by software that attempts to access memory addresses it does not own, or did own but has released.

What to do about CAUSEWAY errors

Feb 2011. I got an eMail from Ray Strackbein saying that he had managed to get around CAUSEWAY errors in Western Digital Disk Diagnostics by temporarily removing Microsoft's memory managers -- himem.sys and emm396.exe -- from the CONFIG.SYS file and rebooting.

So, I guess, if I started getting CAUSEWAY errors, I'd suspect that they are likely the first sign of failing memory. It is common for computer mongers or techs to turn the BIOS memory test off to speed up boot. Microsoft removed the default memory test on boot from Windows 95 for the same reason. The parity bit was removed from most PC memory in the early 1990s in an effort to reduce the then very high cost of memory. (A truly idiotic idea if you ask me -- but no one did). So, most users nowadays are running PCs where no attempt is made to detect faulty memory hardware.

Memory is still tested in Windows SAFE mode. That's surely a large part of why SAFE mode takes so long to start. Remember that BIOS and OS boot up memory tests may fail to detect memory problems that depend on some specific sequence of events. Modern dynamic RAM memory is fairly complex and may well be operating very close to the limits of its capabilities. Failures may occur only under rather complicated scenarios that memory diagnostics may not be able to recreate.

Faced with CAUSEWAY Errors, I'd certainly suspect a bad memory module. If turning on BIOS memory tests and/or Safe Mode boots fail to uncover a problem, one might consider reinstalling the failing program. Beyond that, you're on your own. Good Luck.

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