Of course as soon as I had sent this email it happened again! and a couple of further times. Messages are:-
Not enough quota is available to process this command.
Insufficient system resources exist to complete the requested service
Error 1816 Not enough quota is available to process this command
ONCE: system 32/shfolder.dll is not a valid windows image (AOL unified systray, AOLsoftware.exe (AOL wasn't started)
It seems to be related to the length of time the machine has been on, not specifically Audacity, although programs like Audacity hasten when it happens.
This hotfix on Microsoft appears relevant but you have to apply for it and possibly pay although it is an acknowledged problem in XP SP2.
The portable PC was my work machine which I kept on retirement, and I recently re-installed XP to remove work references so should be fairly clean. I didn't have the problem before. Quota management is not on & I think this problem is to do with internal resources in XP.
If any of your subscribers have any help I would be grateful.
David Llewellyn
Thank you for the very helpful information. I have been unprofessional and not written down the DLL and QUOTA messages. It really happens very infrequently and hasn't happened since I emailed. If it happens again I will send error message details.
In a message dated 22/01/2007 17:41:14 GMT Standard Time, audacity-help@lists.sourceforge.net writes:

    | From DavidWLlewellyn
    | Mon, 22 Jan 2007 04:22:13 EST
    | Subject: [Audacity-help] White noise.
    | I too have very occasionally had the display of the sound  track freeze
    | during recording although I think the sound continued to play,  not associated
    | with white noise.

Recording in real time is very CPU intensive, as is continually redrawing the
waveform of the track as it is recording. You can help display issues by zooming
out to the length you are going to record, and disabling the VU meters at Edit > Preferences > Interface by unchecking "Enable Meter Toolbar".  Some users on
very slow, old systems aren't able to record properly at all unless they minimise

    | What I can get after doing several  recordings (open new window
    | from the file drop down and close previous window)  are error messages
    | following any action that DLLs are corrupt. I have to reboot.  It is as if
    | there is a  memory bleed problem. Windows XP Pro. Audacity 1.2.6.  However
    | it may be a symptom of another problem on my PC where I can get a  problem
    | with the it  reporting a lack of quota although I do not have quotas  enabled
    | or set. XP should be quite clean as I recently reinstalled it as it had  been
    | my portable at work and I wanted to clear all work material off it for home
    | use.

If you'd find it easier you can go to the Interface tab of Preferences and uncheck
"Quit Audacity upon closing last window". Then you can click File > Close, choose
to save or otherwise your current work as a Project, and you will clear the window
to a new empty Project. If you enable this Preference you must then click File >  
Exit to quit Audacity. 

What is the exact text of the error messages you get about dll's and quotas?
Which dll's are reported?

You may also want to review our list of recording tips pasted underneath this

Gale Andrews