# MWClient crash **URL:** \ **Category:** Support\ **Created:** [September 6, 2017, 3:12pm UTC](https://mworks.discourse.group/t/mwclient-crash/381 "2017-09-06T15:12:59Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [September 6, 2017, 3:12pm UTC](https://mworks.discourse.group/t/mwclient-crash/381/1 "2017-09-06T15:12:59Z")
Hi Chris, In the latest nightly, using both a server-embedded-python script and a client bridge python script we saw a crash with the below backtrace: This is somewhat high priority for us as if it recurs it will prevent us from using the latest nightly/python embed. It only happened after an experiment had run quite a few trials, so I don’t know how we can deliver a test case. Ideas? Happy to talk about ways to help. thanks, Mark Process: MWClient [829] Path: /Applications/MWClient.app/Contents/MacOS/MWClient Identifier: org.mworks-project.MWClient Version: 0.8.dev-20170825 (da0d4a25) Code Type: X86-64 (Native) Parent Process: ??? [1] Responsible: MWClient [829] User ID: 502 Date/Time: 2017-08-31 11:20:15.166 -0400 OS Version: Mac OS X 10.12.6 (16G29) Report Version: 12 Anonymous UUID: 423A48BD-7D2F-7720-89F8-36005FA478AB Time Awake Since Boot: 3600 seconds System Integrity Protection: enabled Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC\_BAD\_ACCESS (SIGSEGV) Exception Codes: KERN\_INVALID\_ADDRESS at 0x0000000000000000 Exception Note: EXC\_CORPSE\_NOTIFY Termination Signal: Segmentation fault: 11 Termination Reason: Namespace SIGNAL, Code 0xb Terminating Process: exc handler [0] VM Regions Near 0: → \_\_TEXT 0000000106440000-000000010645d000 [116K] r-x/rwx SM=COW /Applications/MWClient.app/Contents/MacOS/MWClient Application Specific Information: Performing @selector(\_outlineControlClicked:) from sender NSButton 0x610000341ad0 Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 libsystem\_c.dylib 0x00007fff8cf08b52 strlen + 18 1 org.mworks-project.MWorksCocoa 0x0000000106a62877 -[MWCodec valueForVariable:] + 159 2 com.yourcompany.yourcocoabundle 0x000000010cc6b3bf -[MWVariablesWindowController setValue:forVariable:] + 244 3 com.yourcompany.yourcocoabundle 0x000000010cc69d41 -[MWVariablesWindowController controlTextDidEndEditing:] + 434 4 com.apple.CoreFoundation 0x00007fff7776845c **CFNOTIFICATIONCENTER\_IS\_CALLING\_OUT\_TO\_AN\_OBSERVER** + 12 5 com.apple.CoreFoundation 0x00007fff7776835b \_CFXRegistrationPost + 427 6 com.apple.CoreFoundation 0x00007fff777680c2 \_\_\_CFXNotificationPost\_block\_invoke + 50 7 com.apple.CoreFoundation 0x00007fff77725523 -[\_CFXNotificationRegistrar find:object:observer:enumerator:] + 1827 8 com.apple.CoreFoundation 0x00007fff7772455c \_CFXNotificationPost + 604 9 com.apple.Foundation 0x00007fff79149677 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66 10 com.apple.AppKit 0x00007fff75417081 -[NSTextField textDidEndEditing:] + 329 11 com.apple.CoreFoundation 0x00007fff7776845c **CFNOTIFICATIONCENTER\_IS\_CALLING\_OUT\_TO\_AN\_OBSERVER** + 12 12 com.apple.CoreFoundation 0x00007fff7776835b \_CFXRegistrationPost + 427 13 com.apple.CoreFoundation 0x00007fff777680c2 \_\_\_CFXNotificationPost\_block\_invoke + 50 ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [September 6, 2017, 5:22pm UTC](https://mworks.discourse.group/t/mwclient-crash/381/2 "2017-09-06T17:22:16Z")
Hi Mark, I think I found the problem. The fix will be in tonight’s nightly build. (FYI, the issue was in the variables window and was not related to any Python stuff.) Chris ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [September 6, 2017, 5:52pm UTC](https://mworks.discourse.group/t/mwclient-crash/381/3 "2017-09-06T17:52:40Z")
Excellent. It only happened to us once or twice but we are very happy to have a possible fix in. Mark ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [July 19, 2022, 9:53pm UTC](https://mworks.discourse.group/t/mwclient-crash/381/4 "2022-07-19T21:53:00Z")