More info on my problem. If I use children=1, the PHP version still works fine. But the C version still does not. It is a bit better as I can retrieve 3 images before squid blocks the 1st time Then I stop the browser and reload and I get the 2 missing images on the next try. I get the following in the logs: filter: url=/path/to/image1.gif <= only one... 2008/08/19 17:54:35| WARNING: All filter processes are busy. 2008/08/19 17:54:35| WARNING: up to 1 pending requests queued 2008/08/19 17:54:35| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image2.gif'. 2008/08/19 17:54:35| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image3.gif'. 2008/08/19 17:54:35| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image4.gif'. 2008/08/19 17:55:29| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image5.gif'. 2008/08/19 17:55:29| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image2.gif'. 2008/08/19 17:55:29| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image3.gif'. 2008/08/19 17:55:29| aclMatchExternal: 'filter' queue overload. Request rejected '/path/to/image4.gif'. Thx, JD