I have been having this problem for a while. I have seen a number of commands suggested as helpful in various forums: `xwininfo -root -children`, `xlsclients`, and `lsof -U`. I wrote a script that logged the number of lines reported by these every 30 seconds.
It took about 5 days for my computer to crash (for most of which the computer was idle because I was away for the long weekend). xlsclients and lsof stayed steady at around 20 and 500 lines respectively. xwininfo climbed steadily from 68 to 362. When the computer was idle and locked, it would stay steady for hours at a time, then climb by about 10 windows over 5 minutes, then steady out again. As described by Brett Johnson above, most of the windows have no name. I notice that it is always nautilus that crashes, usually while the computer is unattended. I will return, nautilus will be closed and I won't be able to open any new windows because the maximum number of clients is reached. Nautlius exits with a segfault some address "not located in known VMA region". -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1518411 Title: "Maximum number of clients reached", new in Ubuntu 15.10 Status in Compiz: Confirmed Status in compiz package in Ubuntu: Triaged Status in xorg package in Ubuntu: Invalid Bug description: In my newly upgraded (from 15.04) Ubuntu 15.10 system, after I've been logged in for a while I can no longer open new windows and instead get a "Maximum number of clients reached" error. This did not happen in 15.04. I ran "lsof" on the X server and did not see an excessive number of open file descriptors. I ran it again on a newly restarted X server and the number of open file descriptors looked about the same. I also ran "xlsclients" when the X server was reporting "Maximum number of clients reached" and the list of clients looked correct and reasonable (and there were less than 30 of them). I am happy to collect any additional logs or debugging information to help track this down. I don't know where to look further. ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: xserver-xorg 1:7.7+7ubuntu4 ProcVersionSignature: Ubuntu 4.2.0-18.22-generic 4.2.3 Uname: Linux 4.2.0-18-generic x86_64 .tmp.unity.support.test.0: ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins' CompositorRunning: compiz CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0' CompositorUnredirectFSW: true CurrentDesktop: Unity Date: Fri Nov 20 13:00:09 2015 DistUpgraded: 2015-11-17 11:59:09,835 DEBUG enabling apt cron job DistroCodename: wily DistroVariant: ubuntu DkmsStatus: virtualbox, 5.0.4, 3.19.0-33-generic, x86_64: installed virtualbox, 5.0.4, 4.2.0-18-generic, x86_64: installed ExtraDebuggingInterest: Yes GraphicsCard: Intel Corporation Crystal Well Integrated Graphics Controller [8086:0d26] (rev 08) (prog-if 00 [VGA controller]) Subsystem: CLEVO/KAPOK Computer Device [1558:7410] MachineType: System76, Inc. Galago UltraPro ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-18-generic root=UUID=821f94aa-97e2-4384-8494-9f510a75877b ro i915.disable_power_well=0 quiet splash vt.handoff=7 SourcePackage: xorg UpgradeStatus: Upgraded to wily on 2015-11-17 (3 days ago) dmi.bios.date: 12/12/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 4.6.5 dmi.board.asset.tag: Tag 12345 dmi.board.name: W740SU dmi.board.vendor: Notebook dmi.board.version: Not Applicable dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 9 dmi.chassis.vendor: Notebook dmi.chassis.version: N/A dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd12/12/2013:svnSystem76,Inc.:pnGalagoUltraPro:pvrgalu1:rvnNotebook:rnW740SU:rvrNotApplicable:cvnNotebook:ct9:cvrN/A: dmi.product.name: Galago UltraPro dmi.product.version: galu1 dmi.sys.vendor: System76, Inc. version.compiz: compiz 1:0.9.12.2+15.10.20151015-0ubuntu1 version.ia32-libs: ia32-libs N/A version.libdrm2: libdrm2 2.4.64-1 version.libgl1-mesa-dri: libgl1-mesa-dri 11.0.2-1ubuntu4 version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A version.libgl1-mesa-glx: libgl1-mesa-glx 11.0.2-1ubuntu4 version.xserver-xorg-core: xserver-xorg-core 2:1.17.2-1ubuntu9 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.2-1ubuntu1 version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.0+git20150819-0ubuntu1 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20150808-0ubuntu4 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu3 xserver.bootTime: Fri Nov 20 12:51:23 2015 xserver.configfile: default xserver.errors: xserver.logfile: /var/log/Xorg.0.log xserver.version: 2:1.17.2-1ubuntu9 xserver.video_driver: intel To manage notifications about this bug go to: https://bugs.launchpad.net/compiz/+bug/1518411/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp