Sporadic blank window with no signs of error/exception message

[ztanczos]

Description Our users have reported a sporadic issue when an embedded WebView2 fails to render the web content, it just displays a blank page. There is no sign of error messages or exceptions. The WebView2 control seems to be working fine, i.e.: there is a context menu available, DevTools is working but the location is 'about:blank'. Sometimes it takes just one or two restarts to face this issue, sometimes it cannot be reproduced for days.

Version SDK: 1.0.1823.32 Runtime: 114.0.1823.79 and 116.0.1938.62 Framework: WPF OS: Windows 10

Additional info When we enabled chromium logging via additional arguments (--enable-logging --v=1) we see the following entries:

[46936:32128:0907/153649.664:VERBOSE1:embedded_browser_proxy_url_loader_factory.cc(121)] EmbeddedBrowserProxyURLLoaderFactory::CreateLoaderAndStart,proxy: 000043D400BBF7C0, skipped for http://**the*url*we*are*trying*to*open**
[32472:44300:0907/153649.664:VERBOSE1:network_delegate.cc(35)] NetworkDelegate::NotifyBeforeURLRequest: http://**the*url*we*are*trying*to*open**
[46936:32128:0907/153649.683:VERBOSE1:profile_manager.cc(1651)] AddKeepAlive(Default, kClearingBrowsingData). keep_alives=[kBrowserWindow (2), kClearingBrowsingData (1)]
[46936:32128:0907/153649.684:VERBOSE1:edge_dash_service.cc(194)] EdgeDashService::RemoveExtractionsBetween
[46936:32128:0907/153649.684:WARNING:dependency_manager.cc(48)] Trying to register KeyedService Factory: `EdgeBrowserEssentialsSafetyDataManager` after the call to the main registration function `ChromeBrowserMainExtraPartsProfiles::EnsureBrowserContextKeyedServiceFactoriesBuilt()`. Please add a call your factory `KeyedServiceFactory::GetInstance()` in the previous method or to the appropriate `EnsureBrowserContextKeyedServiceFactoriesBuilt()` function to properly register your factory.
[46936:32128:0907/153649.684:VERBOSE1:pref_proxy_config_tracker_impl.cc(191)] 000043D4009EAC00: set chrome proxy config service to 000043D40041F100
[46936:32128:0907/153649.686:WARNING:dependency_manager.cc(48)] Trying to register KeyedService Factory: `CouponsDataManager` after the call to the main registration function `ChromeBrowserMainExtraPartsProfiles::EnsureBrowserContextKeyedServiceFactoriesBuilt()`. Please add a call your factory `KeyedServiceFactory::GetInstance()` in the previous method or to the appropriate `EnsureBrowserContextKeyedServiceFactoriesBuilt()` function to properly register your factory.
[46936:32128:0907/153649.686:VERBOSE1:coupons_data_manager.cc(197)] CouponsDataManager::CouponsDataManager is_bing_identity_valid_for_enroll_: 0 is_rebates_user_: 0
[46936:32128:0907/153649.689:VERBOSE1:embedded_browser_impl.cc(4947)] DidFinishNavigation uncommitted navigation: 3
[32472:44300:0907/153649.698:VERBOSE1:network_delegate.cc(35)] NetworkDelegate::NotifyBeforeURLRequest: http://**a*proxy*url*request**
[46936:51548:0907/153649.730:VERBOSE1:command_storage_backend.cc(927)] Current session files:
[46936:32128:0907/153649.843:VERBOSE1:profile_manager.cc(1702)] RemoveKeepAlive(Default, kClearingBrowsingData). keep_alives=[kBrowserWindow (2)]
[46936:32128:0907/153717.864:VERBOSE1:request_sender.cc(142)] is off the record0

The only suspicious outlier which we don't have in a regular, successful session is this line:

[46936:32128:0907/153649.689:VERBOSE1:embedded_browser_impl.cc(4947)] DidFinishNavigation uncommitted navigation: 3

Unfortunately searching the internet with this log entry did not help.

Any help on how to fix or how to further troubleshoot this problem would be greatly appreciated.

Thanks, Zoltan

[pontusn]

Sounds familiar, we have noticed intermittent aborted navigations, possibly related to race-conditions during initialization.

[ztanczos]

Thanks @pontusn, yes it seems we also had something similar. We re-ordered our initialization logic and the issue disappeared. We suspect that that the ClearBrowsingDataAsync() call was still running when we triggered the navigation which - in some non-deterministic cases cancelled it.