Hello,
I'm also having an issue with launching Cura 3.0.4 (The problem started from the 3.7 update). As soon as Cura is launched it exits. The only way I can start the application is by disabling my wifi connection. It then starts normally but the moment I enable wifi again the application exits again.
I have whitelisted Cura in the Firewall setting but the issue still persists. This is occurring on a MacBook Pro macOS version 10.12.6
This is the stack trace
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x00007fffa6bddd42 __pthread_kill + 10
1 libsystem_c.dylib 0x00007fffa6af4497 raise + 26
2 libsystem_platform.dylib 0x00007fffa6cbeb3a _sigtramp + 26
3 ??? 000000000000000000 0 + 0
4 com.apple.CFNetwork 0x00007fff905e95c4 PAC::PACClient::invokeClientCallback() + 102
5 com.apple.CoreFoundation 0x00007fff91347321 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
6 com.apple.CoreFoundation 0x00007fff9132821d __CFRunLoopDoSources0 + 557
7 com.apple.CoreFoundation 0x00007fff91327716 __CFRunLoopRun + 934
8 com.apple.CoreFoundation 0x00007fff91327114 CFRunLoopRunSpecific + 420
9 libQt5Network.5.dylib 0x0000000109114d75 0x109070000 + 675189
10 libQt5Network.5.dylib 0x0000000109115b51 QNetworkProxyFactory::systemProxyForQuery(QNetworkProxyQuery const&) + 17
11 libQt5Network.5.dylib 0x000000010910b753 0x109070000 + 636755
12 libQt5Network.5.dylib 0x000000010910d842 QNetworkProxyFactory::proxyForQuery(QNetworkProxyQuery const&) + 50
13 libQt5Network.5.dylib 0x00000001090a155e 0x109070000 + 202078
14 libQt5Network.5.dylib 0x00000001090bf329 0x109070000 + 324393
15 libQt5Network.5.dylib 0x00000001090c4283 0x109070000 + 344707
16 libQt5Network.5.dylib 0x00000001090bbdee 0x109070000 + 310766
17 libQt5Network.5.dylib 0x00000001090bba9b 0x109070000 + 309915
18 libQt5Network.5.dylib 0x000000010909fed5 QNetworkAccessManager::createRequest(QNetworkAccessManager::Operation, QNetworkRequest const&, QIODevice*) + 1653
19 PyQt5.QtNetwork.so 0x0000000108fccef1 sipQNetworkAccessManager::createRequest(QNetworkAccessManager::Operation, QNetworkRequest const&, QIODevice*) + 129
20 libQt5Network.5.dylib 0x000000010909e2de QNetworkAccessManager::get(QNetworkRequest const&) + 30
21 PyQt5.QtNetwork.so 0x0000000108fcdd01 meth_QNetworkAccessManager_get(_object*, _object*) + 113
22 nl.ultimaker.cura 0x0000000108a9f0a5 PyCFunction_Call + 165
23 nl.ultimaker.cura