Titanium JIRA Archive
Titanium SDK/CLI (TIMOB)

[TIMOB-3474] _WebTryThreadLock Crash when going BACK from WebView window

GitHub Issuen/a
ResolutionCannot Reproduce
Resolution Date2017-01-03T11:20:58.000+0000
Affected Version/sn/a
Fix Version/sn/a
AssigneeIngo Muschenetz


I have a table view with a form and on submit it brings the user to a webview that shows results. That works great. But when the user goes BACK to the form. It appears for a second and then crashes with the following result. This was working great in versions prior to 1.6 but since 1.6 its been crashing.

2011-03-18 22:04:56.252 APPNAME [58306:7003] bool _WebTryThreadLock(bool),
0x6c64cc0: Tried to obtain the web lock from a thread other than the main thread or the web
thread. This may be a result of calling to UIKit from a secondary thread. Crashing now...

Note that this bug only happens when on click I was creating window object and then use an JS file for the url parameter and opening the window. When that window opens the JS file, that file used the current window and built the webview.

That used to work fine but now when I go BACK from that webview to the prev screen I'd get the _webtrythreadlock error.

So what I did was remove the JS file and simply create the webview on the click event instead. I like to keep things clean and use JS files to keep things organized but In this case its causing the crash it seems.

This is happening in v1.6 and v1.7. I hope I'm correct and this helps. Thanks


  1. Slim McKinsley 2011-09-09

    Use case: http://pastie.org/2509737 For additional info, see this Q&A post: http://developer.appcelerator.com/question/117475/webtrythreadlock-crash-when-going-back-from-webview-window
  2. Hans Knöchel 2017-01-03

    Not reproducible in recent versions of the SDK (6.0.1.GA / 6.1.0 master).
  3. Lee Morris 2017-03-23

    Can verify this ticket as "Cannot Reproduce". Tested with the following environment; iPhone 7 and Simulator (10.2) MacOS 10.11.6 (15G31) Studio Ti SDK 6.0.3 GA Appc NPM 4.2.8 Appc CLI 6.1.0 Ti CLI 5.0.11 Alloy 1.9.5 Arrow 1.10.1 Xcode 8.2 (8C38) Node v4.6.0 Java 1.7.0_80

JSON Source