I've seen this twice now in the last two days using my work OWA. Will try to create a postable testcase. ASSERTION FAILED: docLoader->requestCount() == 0 (/Volumes/Store/Code/WebKit/WebCore/loader/loader.cpp:178 void WebCore::Loader::cancelRequests(WebCore::DocLoader*)) Thread 0 Crashed: 0 com.apple.WebCore 0x03cb9f6c WebCore::Loader::cancelRequests(WebCore::DocLoader*) + 350 (loader.cpp:178) 1 com.apple.WebCore 0x036d9450 WebCore::FrameLoader::stopLoading(bool) + 784 (FrameLoader.cpp:616) 2 com.apple.WebCore 0x0364ddbf WebCore::DocumentLoader::stopLoading() + 125 (DocumentLoader.cpp:299) 3 com.apple.WebCore 0x036d0470 WebCore::FrameLoader::stopAllLoaders() + 148 (FrameLoader.cpp:2690) 4 com.apple.WebCore 0x036d0725 WebCore::FrameLoader::continueLoadAfterNavigationPolicy(WebCore::ResourceRequest const&, WTF::PassRefPtr<WebCore::FormState>, bool) + 615 (FrameLoader.cpp:4074) 5 com.apple.WebCore 0x036d089e WebCore::FrameLoader::callContinueLoadAfterNavigationPolicy(void*, WebCore::ResourceRequest const&, WTF::PassRefPtr<WebCore::FormState>, bool) + 70 (FrameLoader.cpp:4027) 6 com.apple.WebCore 0x036cdf26 WebCore::PolicyCheck::call(bool) + 110 (FrameLoader.cpp:5064) 7 com.apple.WebCore 0x036d139d WebCore::FrameLoader::continueAfterNavigationPolicy(WebCore::PolicyAction) + 397 (FrameLoader.cpp:4020) 8 com.apple.WebKit 0x001c630a WebFrameLoaderClient::receivedPolicyDecison(WebCore::PolicyAction) + 310 (WebFrameLoaderClient.mm:1098) 9 com.apple.WebKit 0x001c93cc -[WebFramePolicyListener receivedPolicyDecision:] + 134 (WebFrameLoaderClient.mm:1668) 10 com.apple.WebKit 0x001c3f44 -[WebFramePolicyListener use] + 44 (WebFrameLoaderClient.mm:1684) 11 com.apple.CoreFoundation 0x971fea3d __invoking___ + 29 12 com.apple.CoreFoundation 0x971fe428 -[NSInvocation invoke] + 136 13 com.apple.CoreFoundation 0x971fe4f8 -[NSInvocation invokeWithTarget:] + 72 14 com.apple.WebKit 0x002406cf -[_WebSafeForwarder forwardInvocation:] + 273 (WebView.mm:2096) 15 com.apple.CoreFoundation 0x971fe96a ___forwarding___ + 986 16 com.apple.CoreFoundation 0x971fe9d2 _CF_forwarding_prep_0 + 50 17 com.apple.WebKit 0x001c98fa WebFrameLoaderClient::dispatchDecidePolicyForNavigationAction(void (WebCore::FrameLoader::*)(WebCore::PolicyAction), WebCore::NavigationAction const&, WebCore::ResourceRequest const&, WTF::PassRefPtr<WebCore::FormState>) + 238 (WebFrameLoaderClient.mm:676) 18 com.apple.WebCore 0x036d1b8f WebCore::FrameLoader::checkNavigationPolicy(WebCore::ResourceRequest const&, WebCore::DocumentLoader*, WTF::PassRefPtr<WebCore::FormState>, void (*)(void*, WebCore::ResourceRequest const&, WTF::PassRefPtr<WebCore::FormState>, bool), void*) + 753 (FrameLoader.cpp:3989) 19 com.apple.WebCore 0x036d24df WebCore::FrameLoader::loadWithDocumentLoader(WebCore::DocumentLoader*, WebCore::FrameLoadType, WTF::PassRefPtr<WebCore::FormState>) + 707 (FrameLoader.cpp:2419) 20 com.apple.WebCore 0x036d2a94 WebCore::FrameLoader::loadWithNavigationAction(WebCore::ResourceRequest const&, WebCore::NavigationAction const&, WebCore::FrameLoadType, WTF::PassRefPtr<WebCore::FormState>) + 270 (FrameLoader.cpp:2355) 21 com.apple.WebCore 0x036d5a4f WebCore::FrameLoader::loadURL(WebCore::KURL const&, WebCore::String const&, WebCore::String const&, WebCore::FrameLoadType, WebCore::Event*, WTF::PassRefPtr<WebCore::FormState>) + 1055 (FrameLoader.cpp:2303) 22 com.apple.WebCore 0x036d58be WebCore::FrameLoader::loadURL(WebCore::KURL const&, WebCore::String const&, WebCore::String const&, WebCore::FrameLoadType, WebCore::Event*, WTF::PassRefPtr<WebCore::FormState>) + 654 (FrameLoader.cpp:2282) 23 com.apple.WebCore 0x036d71d7 WebCore::FrameLoader::loadFrameRequestWithFormAndValues(WebCore::FrameLoadRequest const&, bool, WebCore::Event*, WebCore::HTMLFormElement*, WTF::HashMap<WebCore::String, WebCore::String, WebCore::StringHash, WTF::HashTraits<WebCore::String>, WTF::HashTraits<WebCore::String> > const&) + 955 (FrameLoader.cpp:2251) 24 com.apple.WebCore 0x036daf69 WebCore::FrameLoader::urlSelected(WebCore::FrameLoadRequest const&, WebCore::Event*, bool) + 265 (FrameLoader.cpp:396) 25 com.apple.WebCore 0x036db090 WebCore::FrameLoader::urlSelected(WebCore::ResourceRequest const&, WebCore::String const&, WebCore::Event*, bool, bool) + 264 (FrameLoader.cpp:410) 26 com.apple.WebCore 0x03708f02 WebCore::HTMLAnchorElement::defaultEventHandler(WebCore::Event*) + 2104 (HTMLAnchorElement.cpp:221) 27 com.apple.WebCore 0x03685c86 WebCore::EventTargetNode::dispatchGenericEvent(WTF::PassRefPtr<WebCore::Event>) + 2064 (EventTargetNode.cpp:387) 28 com.apple.WebCore 0x03685e95 WebCore::EventTargetNode::dispatchEvent(WTF::PassRefPtr<WebCore::Event>, int&) + 323 (EventTargetNode.cpp:273) 29 com.apple.WebCore 0x036887b7 WebCore::EventTargetNode::dispatchMouseEvent(WebCore::AtomicString const&, int, int, int, int, int, int, bool, bool, bool, bool, bool, WebCore::Node*, WTF::PassRefPtr<WebCore::Event>) + 869 (EventTargetNode.cpp:579) 30 com.apple.WebCore 0x03688feb WebCore::EventTargetNode::dispatchMouseEvent(WebCore::PlatformMouseEvent const&, WebCore::AtomicString const&, int, WebCore::Node*) + 511 (EventTargetNode.cpp:488) 31 com.apple.WebCore 0x0367a07b WebCore::EventHandler::dispatchMouseEvent(WebCore::AtomicString const&, WebCore::Node*, bool, int, WebCore::PlatformMouseEvent const&, bool) + 145 (EventHandler.cpp:1534) 32 com.apple.WebCore 0x0367abaa WebCore::EventHandler::handleMouseDoubleClickEvent(WebCore::PlatformMouseEvent const&) + 560 (EventHandler.cpp:1137) 33 com.apple.WebCore 0x03681a8c WebCore::EventHandler::mouseUp(NSEvent*) + 386 (EventHandlerMac.mm:534) 34 com.apple.WebKit 0x001e1af8 -[WebHTMLView mouseUp:] + 274 (WebHTMLView.mm:3308) 35 com.apple.WebCore 0x03683110 WebCore::EventHandler::passSubframeEventToSubframe(WebCore::MouseEventWithHitTestResults&, WebCore::Frame*, WebCore::HitTestResult*) + 940 (EventHandlerMac.mm:425) 36 com.apple.WebCore 0x03683309 WebCore::EventHandler::passMousePressEventToSubframe(WebCore::MouseEventWithHitTestResults&, WebCore::Frame*) + 39 (EventHandlerMac.mm:633) 37 com.apple.WebCore 0x0367aa6c WebCore::EventHandler::handleMouseDoubleClickEvent(WebCore::PlatformMouseEvent const&) + 242 (EventHandler.cpp:1126) 38 com.apple.WebCore 0x03681a8c WebCore::EventHandler::mouseUp(NSEvent*) + 386 (EventHandlerMac.mm:534) 39 com.apple.WebKit 0x001e1af8 -[WebHTMLView mouseUp:] + 274 (WebHTMLView.mm:3308) 40 com.apple.AppKit 0x91da5241 -[NSWindow sendEvent:] + 5539 41 com.apple.Safari 0x000294a3 0x1000 + 165027 42 com.apple.AppKit 0x91d71d49 -[NSApplication sendEvent:] + 2941 43 com.apple.Safari 0x00029020 0x1000 + 163872 44 com.apple.AppKit 0x91ccf69f -[NSApplication run] + 847 45 com.apple.AppKit 0x91c9c8a4 NSApplicationMain + 574 46 com.apple.Safari 0x000b2776 0x1000 + 726902