Xcode 8 beta IDE crashes consistently

I haven't done the extensive crash log reviews that you've done, but I'm experiencing the same crashing behavior on an almost identical Macbook Pro (with 8GB RAM). It's unusably slow, requiring 10-15 seconds to go from one tab to another, edit changes of a character or two result in up to 30 seconds of the spinning beachball and often such an editing changes hang Xcode up until I have to do a force quit. It seems to be a little better working with Objective C, but with Swift 3.0: unusable.

I'm currently downloading another .xib file in the hopes that maybe the last download install was corrupt, but I know the chances of that are nil. I'm hoping for an update soon that will be better for this machine.

Hmmm....Haven't experienced the dreaded beachball yet. I desperately downloaded twice also, but to no avail.

This is definitely language sensistive even though I recently duplicated the bug in a mixed language project perusing a .mm file.

I suspect it may be source related since I get spurious SourceKit and DVTKit related notices in the system log and crash logs like:

The following syslog captures the entire Xcode session start to crash (yes it takes me less than a minute to duplicate):

Marker - Jun 16, 2016, 4:29:00 PM
Jun 16 16:29:07 Taurine ***[689]: LaunchServices: Could not store ***-identifiers file at /private/var/db/***/com.apple.lsdschemes.plist
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested watch is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested phone is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested watch is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested phone is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested watch is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested phone is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested watch is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested phone is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:08 Taurine com.apple.CoreSimulator.CoreSimulatorService[3399]: Requested watch is is not available for pairing.  Assuming it has the capability.
Jun 16 16:29:09 --- last message repeated 1 time ---
Jun 16 16:29:09 Taurine GPUToolsAgent[63336]: Mac Agent inited !!!
Jun 16 16:29:09 Taurine com.apple.usbmuxd[85]: MuxTCPInputSCE received RST for 0x1-5792ddcfd8db6d7fd1101251ca746ca266785248@0x24100000:57677->0x7fd34a51f570-Xcode/com.apple.dt.Xcode:57344: sendMuxSegment connection was closed
Jun 16 16:29:19 Taurine Xcode[63333]: schedule invalidation <DYTransport 0x7f903c214b60, error: explicit invalidation (6)>
Jun 16 16:29:38 Taurine Xcode[63333]: Unknown class GPUTesselationSliderCell in Interface Builder file.
Jun 16 16:29:41 Taurine sourcekit-serv[63435]: [1:getCursorInfo:11571: 0.0000] failed to create an ASTInvocation: '/Users/Me/Development/iOS/Lux/Framework/XCode8Beta/ParticleLab/MetalParticles/ViewController.swift' is not part of the input files
Jun 16 16:29:41 Taurine sourcekit-serv[63435]: [1:getCursorInfo:11059: 0.0014] failed to create an ASTInvocation: '/Users/Me/Development/iOS/Lux/Framework/XCode8Beta/ParticleLab/MetalParticles/ViewController.swift' is not part of the input files
Jun 16 16:29:41 Taurine sourcekit-serv[63435]: [1:getCursorInfo:10295: 0.0015] failed to create an ASTInvocation: '/Users/Me/Development/iOS/Lux/Framework/XCode8Beta/ParticleLab/MetalParticles/ViewController.swift' is not part of the input files
Jun 16 16:29:41 Taurine sourcekit-serv[63435]: [1:getCursorInfo:4695: 0.0017] failed to create an ASTInvocation: '/Users/Me/Development/iOS/Lux/Framework/XCode8Beta/ParticleLab/MetalParticles/ViewController.swift' is not part of the input files
Jun 16 16:29:47 Taurine sourcekit-serv[63435]: [1:handlePrimaryAST:8627: 5.6781] did not find document snapshot when handling the AST
Jun 16 16:29:49 Taurine GPUToolsAgent[63336]: schedule invalidation <DYTransport 0x7fbd0ad13ff0, error: lost transport connection (31)>
Jun 16 16:29:49 Taurine com.apple.xpc.launchd[1] (com.apple.dt.Xcode.602272[63333]): Service exited due to signal: Segmentation fault: 11
Jun 16 16:29:49 Taurine com.apple.xpc.launchd[1] (com.apple.ReportCrash[63487]): Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.ReportCrash
Jun 16 16:29:50 Taurine com.apple.xpc.launchd[1] (com.apple.SourceKitService.800.0.30[63435]): Service exited due to signal: Killed: 9
Jun 16 16:29:50 Taurine ReportCrash[63487]: Saved crash report for Xcode[63333] version 8.0 (11160.22) to /Users/Me/Library/Logs/DiagnosticReports/Xcode_2016-06-16-162950_Taurine.crash
Jun 16 16:29:50 Taurine ReportCrash[63487]: AutoSubmitPreference is 0

Xcode 7.3.1 performs like a champ. A little sluggish from time to time but can't complain. My old book benefited greatly from fast SSD and 8GB. Still a little life left in her...Sorry that Apple has decided to leave us behind for Sierra (Seriously!)

Are you running on El Cap 10.11.5?

Wondering if we are suffering from planned obsolescence?

I can't believe this is planned - or unplanned - obsolence, as 7.3.1 runs so well. I am, indeed, runninng El Cap 10.11.5, as you. I think our MacBooks are the same vintage, both with 8GB and an SSD. I usually develop on a MacPro (older than this MacBook, but still a great machine), but I don't have access to it now so I can't tell how Xcode 8 works on it. I am surprised that you and I are the only ones commenting on these problems; I can't imagine there's something so unusual about our MacBooks that the probems are occurring only to us!

Downloading and re-installing had no effect for me, either.

I am experiencing the same issue with xCode 8 beta on a 2012 Macbook pro with 16gb of ram and an SSD

I found the problem for my situation, and unfortunately, I think it's not going to help other with crashes.

At some point I downloaded from the device the container for the app to look at what was there. This is a static map-based app and so there are about 121,000 map tiles in the xcappdata file that container. Somehow - I'm sure it could not possibly have been anything I did, or more likely it was - that xcappdata container got into my git repository, even though they were never added to the project. (I may have generated a git repository and initial commit manually; honestly, I can't remember.) Then I deleted that container without doing a git rm. I realized that Xcode was showing 121,000 missing files in the Issue Navigator. Evidently, every freaking change I tried to make caused Xcode to update the Issue Navigator, which, with 121,000 entries, took a long time and sometimes just died doing it.

So today I got the deleted files out of the repository, and Xcode is now behaving perfectly well. My code is behaving less well, but that's my problem, not Xcode's.

Wish I had an answer for the crashing behavior, but I'm afraid I don't.

Glad you made some headway on your end. Yes, git and xcode sometimes don't play nice (still!)

To eliminate the possibility of a corrupt project, I made sure to open brand new 2016 Apple sample projects.

I have filed a bug report to tickle the *****. Hope this gets adressed soon cause I'm stuck...

I have been seeing the same behavior. Crash is always associated with an NSURLSession Event

Thread 24 Crashed:: Dispatch queue: com.apple.NSURLSession-work

0 com.apple.CFNetwork 0x00007fff9e522036 SessionConnectionLoadable::_loaderClientEvent_asyncError(__CFString const*, long) + 62

Also the crash I experience is always in the editor while I am trying to edit code. I think it may have something to do with auto complete and syntax checking calling out to apple.com for document info and failing somehow.

Same here. When I load a certain project, I just see the spinning wheel and the beachball. However, when I then disable WiFi, the project loads instantly. MacBook Pro 15" Mid 2015...

I couldn't open a project without Xcode freezing, and this worked for me! Thanks so much