Thanks for the report, but considering what changes there are in Dolphin's code between 4.10.0 and 4.10.1 and that I haven't seen any such freezes yet, I think it's quite unlikely that it's Dolphin's fault.

I assume that one of the "Actions" plugins for the context menu is the culprit. To find out which one it is, you could remove them one by one (Settings dialog, "Services" section) and test after each removal if the freezing disappears.

Alternatively, you could run Dolphin in gdb and get a backtrace during the freeze.

It might have something to do with me activating Nepomuk again. I had to deactivate it in 4.10.0 because a bug made it crash all the time. This bug is fixed now, so I activated it.

How do I use gdb?

In a terminal, type:

gdb dolphin

At the gdb prompt, enter 'r' (short for 'run') + Enter

Reproduce the freeze, then in the gdb terminal, press Ctrl+Z, wait until the gdb prompt appears, then type 'thread apply all bt' + Enter.

This should show you the backtrace of all threads at the time of the freeze, including the stack frames in the GUI thread where the freeze happens.

If there is some KActivities-related stuff in the backtrace, it might be bug 314575. If you just want to check that and save yourself the gdb trouble, you can also just disable the Activities actions and see if that helps.

[New Thread 0x7fffd6794700 (LWP 30861)]
[Thread 0x7fffd6794700 (LWP 30861) exited]
dolphin(30534)/kdecore (services) KServicePrivate::init: The desktop entry file  "/home/mark/Musik/.directory"  has Type= "Application"  but no Exec line 

dolphin(30534) KConfigGroup::readXdgListEntry: List entry MimeType in "/home/mark/.kde/share/kde4/services/ServiceMenus/118537-image2pdf.desktop" is not compliant with XDG standard (missing trailing semicolon). 
^Z
Program received signal SIGTSTP, Stopped (user).
0x00007ffff7863313 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
87      ../sysdeps/unix/sysv/linux/poll.c: Datei oder Verzeichnis nicht gefunden.
(gdb) thread apply all bt

Thread 3 (Thread 0x7fffd7b71700 (LWP 30600)):
#0  0x00007ffff7863313 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007fffef06cd84 in g_main_context_poll (n_fds=2, fds=0x7fffd00029b0, timeout=-1, context=0x7fffd00009a0, priority=<optimized out>)
    at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3584
#2  g_main_context_iterate (context=context@entry=0x7fffd00009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3285
#3  0x00007fffef06cea4 in g_main_context_iteration (context=0x7fffd00009a0, may_block=1) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3351
#4  0x00007ffff3743c46 in QEventDispatcherGlib::processEvents (this=0x7fffd00008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#5  0x00007ffff37142ef in QEventLoop::processEvents (this=this@entry=0x7fffd7b70dd0, flags=...) at kernel/qeventloop.cpp:149
#6  0x00007ffff3714578 in QEventLoop::exec (this=0x7fffd7b70dd0, flags=...) at kernel/qeventloop.cpp:204
#7  0x00007ffff3615b40 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#8  0x00007ffff36f49df in QInotifyFileSystemWatcherEngine::run (this=0xd16b70) at io/qfilesystemwatcher_inotify.cpp:248
#9  0x00007ffff3618b1c in QThreadPrivate::start (arg=0xd16b70) at thread/qthread_unix.cpp:338
#10 0x00007fffef53be9a in start_thread (arg=0x7fffd7b71700) at pthread_create.c:308
#11 0x00007ffff786eccd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7fffdccf3700 (LWP 30599)):
#0  0x00007ffff7863313 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007fffef06cd84 in g_main_context_poll (n_fds=2, fds=0x7fffd8002bb0, timeout=-1, context=0x7fffd80009a0, priority=<optimized out>)
    at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3584
#2  g_main_context_iterate (context=context@entry=0x7fffd80009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3285
#3  0x00007fffef06cea4 in g_main_context_iteration (context=0x7fffd80009a0, may_block=1) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3351
#4  0x00007ffff3743c46 in QEventDispatcherGlib::processEvents (this=0x7fffd80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#5  0x00007ffff37142ef in QEventLoop::processEvents (this=this@entry=0x7fffdccf2dd0, flags=...) at kernel/qeventloop.cpp:149
#6  0x00007ffff3714578 in QEventLoop::exec (this=0x7fffdccf2dd0, flags=...) at kernel/qeventloop.cpp:204
#7  0x00007ffff3615b40 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#8  0x00007ffff36f49df in QInotifyFileSystemWatcherEngine::run (this=0xac60e0) at io/qfilesystemwatcher_inotify.cpp:248
#9  0x00007ffff3618b1c in QThreadPrivate::start (arg=0xac60e0) at thread/qthread_unix.cpp:338
#10 0x00007fffef53be9a in start_thread (arg=0x7fffdccf3700) at pthread_create.c:308
#11 0x00007ffff786eccd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7ffff7fa3780 (LWP 30534)):
#0  0x00007ffff7863313 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007fffed8913d0 in ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
#2  0x00007fffed89029d in ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
#3  0x00007fffed87afa4 in ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
#4  0x00007fffed87c34d in ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
#5  0x00007ffff333e556 in q_dbus_pending_call_block (pending=<optimized out>) at qdbus_symbols_p.h:313
#6  QDBusConnectionPrivate::waitForFinished (this=0x781890, pcall=0x1842f70) at qdbusintegrator.cpp:1778
#7  0x00007ffff337d8f7 in QDBusPendingCallPrivate::waitForFinished (this=0x1842f70) at qdbuspendingcall.cpp:245
#8  0x00007ffff59077e0 in KActivities::Consumer::isResourceLinkedToActivity(QUrl const&, QString const&) const () from /usr/lib/libkactivities.so.6
#9  0x00007fffd5b75f3e in ?? () from /usr/lib/kde4/kactivitymanagerd_fileitem_linking_plugin.so
#10 0x00007ffff7b87158 in DolphinContextMenu::addFileItemPluginActions (this=this@entry=0x1777e40) at ../../../dolphin/src/dolphincontextmenu.cpp:500
#11 0x00007ffff7b87885 in DolphinContextMenu::openItemContextMenu (this=0x1777e40) at ../../../dolphin/src/dolphincontextmenu.cpp:277
#12 0x00007ffff7b88105 in DolphinContextMenu::open (this=0x1777e40) at ../../../dolphin/src/dolphincontextmenu.cpp:137
#13 0x00007ffff7b7ddca in DolphinMainWindow::openContextMenu (this=0x7d0570, pos=..., item=..., url=..., customActions=...) at ../../../dolphin/src/dolphinmainwindow.cpp:1298
#14 0x00007ffff7b80ca9 in qt_static_metacall (_a=<optimized out>, _id=<optimized out>, _o=<optimized out>, _c=<optimized out>) at ./dolphinmainwindow.moc:256
#15 DolphinMainWindow::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at ./dolphinmainwindow.moc:177
#16 0x00007ffff372af8f in QMetaObject::activate (sender=0xef5940, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fffffffb970) at kernel/qobject.cpp:3547
---Type <return> to continue, or q <return> to quit---
#17 0x00007ffff6bc9ca4 in DolphinView::requestContextMenu (this=this@entry=0xef5940, _t1=..., _t2=..., _t3=..., _t4=...) at ./dolphinview.moc:447
#18 0x00007ffff6bca621 in DolphinView::slotItemContextMenuRequested (this=0xef5940, index=<optimized out>, pos=...) at ../../../dolphin/src/views/dolphinview.cpp:838
#19 0x00007ffff6bceec4 in qt_static_metacall (_a=<optimized out>, _id=<optimized out>, _o=<optimized out>, _c=<optimized out>) at ./dolphinview.moc:246
#20 DolphinView::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at ./dolphinview.moc:191
#21 0x00007ffff372af8f in QMetaObject::activate (sender=0xef8670, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fffffffbb70) at kernel/qobject.cpp:3547
#22 0x00007ffff6b95ba6 in KItemListController::itemContextMenuRequested (this=this@entry=0xef8670, _t1=5, _t2=...) at ./kitemlistcontroller.moc:232
#23 0x00007ffff6b970ca in KItemListController::mousePressEvent (this=0xef8670, event=0x7fffffffc9a0, transform=...) at ../../../dolphin/src/kitemviews/kitemlistcontroller.cpp:606
#24 0x00007ffff6b94c2e in KItemListController::processEvent (this=0xef8670, event=0x1, event@entry=0x7fffffffc9a0, transform=...)
    at ../../../dolphin/src/kitemviews/kitemlistcontroller.cpp:997
#25 0x00007ffff6b9c6ab in KItemListView::event (this=0xef6e50, event=0x7fffffffc9a0) at ../../../dolphin/src/kitemviews/kitemlistview.cpp:868
#26 0x00007ffff40f7e9c in QApplicationPrivate::notify_helper (this=this@entry=0x639880, receiver=receiver@entry=0xef6e50, e=e@entry=0x7fffffffc9a0) at kernel/qapplication.cpp:4562
#27 0x00007ffff40fc30a in QApplication::notify (this=0x7fffffffdf60, receiver=0xef6e50, e=0x7fffffffc9a0) at kernel/qapplication.cpp:4423
#28 0x00007ffff4e00ad6 in KApplication::notify (this=0x7fffffffdf60, receiver=0xef6e50, event=0x7fffffffc9a0) at ../../kdeui/kernel/kapplication.cpp:311
#29 0x00007ffff371559e in QCoreApplication::notifyInternal (this=0x7fffffffdf60, receiver=0xef6e50, event=0x7fffffffc9a0) at kernel/qcoreapplication.cpp:915
#30 0x00007ffff46e0d6b in sendEvent (event=0x7fffffffc9a0, item=0xef6e60, this=<optimized out>) at graphicsview/qgraphicsscene.cpp:1217
#31 QGraphicsScenePrivate::sendEvent (this=<optimized out>, item=0xef6e60, event=0x7fffffffc9a0) at graphicsview/qgraphicsscene.cpp:1197
#32 0x00007ffff46e1950 in sendMouseEvent (mouseEvent=0x7fffffffc9a0, this=0xefe290) at graphicsview/qgraphicsscene.cpp:1295
#33 QGraphicsScenePrivate::sendMouseEvent (this=0xefe290, mouseEvent=0x7fffffffc9a0) at graphicsview/qgraphicsscene.cpp:1274
#34 0x00007ffff46e7b06 in QGraphicsScenePrivate::mousePressEventHandler (this=this@entry=0xefe290, mouseEvent=mouseEvent@entry=0x7fffffffc9a0) at graphicsview/qgraphicsscene.cpp:1422
#35 0x00007ffff46e800f in QGraphicsScene::mousePressEvent (this=<optimized out>, mouseEvent=0x7fffffffc9a0) at graphicsview/qgraphicsscene.cpp:4074
#36 0x00007ffff46f515a in QGraphicsScene::event (this=0xefe0b0, event=0x7fffffffc9a0) at graphicsview/qgraphicsscene.cpp:3455
#37 0x00007ffff40f7e9c in QApplicationPrivate::notify_helper (this=this@entry=0x639880, receiver=receiver@entry=0xefe0b0, e=e@entry=0x7fffffffc9a0) at kernel/qapplication.cpp:4562
#38 0x00007ffff40fc30a in QApplication::notify (this=0x7fffffffdf60, receiver=0xefe0b0, e=0x7fffffffc9a0) at kernel/qapplication.cpp:4423
#39 0x00007ffff4e00ad6 in KApplication::notify (this=0x7fffffffdf60, receiver=0xefe0b0, event=0x7fffffffc9a0) at ../../kdeui/kernel/kapplication.cpp:311
#40 0x00007ffff371559e in QCoreApplication::notifyInternal (this=0x7fffffffdf60, receiver=0xefe0b0, event=0x7fffffffc9a0) at kernel/qcoreapplication.cpp:915
#41 0x00007ffff4706131 in QGraphicsView::mousePressEvent (this=0xefe9b0, event=0x7fffffffd2d0) at graphicsview/qgraphicsview.cpp:3164
#42 0x00007ffff4147cf3 in QWidget::event (this=0xefe9b0, event=0x7fffffffd2d0) at kernel/qwidget.cpp:8367
#43 0x00007ffff44f6b66 in QFrame::event (this=0xefe9b0, e=0x7fffffffd2d0) at widgets/qframe.cpp:557
#44 0x00007ffff470e95b in QGraphicsView::viewportEvent (this=0xefe9b0, event=0x7fffffffd2d0) at graphicsview/qgraphicsview.cpp:2866
#45 0x00007ffff3715706 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<optimized out>, receiver=0xf147c0, event=0x7fffffffd2d0) at kernel/qcoreapplication.cpp:1025
#46 0x00007ffff40f7e6c in QApplicationPrivate::notify_helper (this=this@entry=0x639880, receiver=receiver@entry=0xf147c0, e=e@entry=0x7fffffffd2d0) at kernel/qapplication.cpp:4558
#47 0x00007ffff40fcb6b in QApplication::notify (this=<optimized out>, receiver=0xf147c0, e=0x7fffffffd2d0) at kernel/qapplication.cpp:4105
#48 0x00007ffff4e00ad6 in KApplication::notify (this=0x7fffffffdf60, receiver=0xf147c0, event=0x7fffffffd2d0) at ../../kdeui/kernel/kapplication.cpp:311
#49 0x00007ffff371559e in QCoreApplication::notifyInternal (this=0x7fffffffdf60, receiver=0xf147c0, event=0x7fffffffd2d0) at kernel/qcoreapplication.cpp:915
#50 0x00007ffff40f8cd3 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#51 QApplicationPrivate::sendMouseEvent (receiver=0xf147c0, event=0x7fffffffd2d0, alienWidget=0xf147c0, nativeWidget=0xed00b0, buttonDown=0x7ffff4bd4308 <qt_button_down>, 
    lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:3173
#52 0x00007ffff4176554 in QETWidget::translateMouseEvent (this=this@entry=0xed00b0, event=event@entry=0x7fffffffda50) at kernel/qapplication_x11.cpp:4622
#53 0x00007ffff417544f in QApplication::x11ProcessEvent (this=0x7fffffffdf60, event=0x7fffffffda50) at kernel/qapplication_x11.cpp:3737
#54 0x00007ffff419cfa2 in x11EventSourceDispatch (s=s@entry=0x6415f0, callback=0x0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#55 0x00007fffef06cab5 in g_main_dispatch (context=0x641820) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:2715
#56 g_main_context_dispatch (context=context@entry=0x641820) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3219
#57 0x00007fffef06cde8 in g_main_context_iterate (context=context@entry=0x641820, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3290
#58 0x00007fffef06cea4 in g_main_context_iteration (context=0x641820, may_block=1) at /build/buildd/glib2.0-2.34.1/./glib/gmain.c:3351
#59 0x00007ffff3743c26 in QEventDispatcherGlib::processEvents (this=0x608b10, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#60 0x00007ffff419cc1e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#61 0x00007ffff37142ef in QEventLoop::processEvents (this=this@entry=0x7fffffffde20, flags=...) at kernel/qeventloop.cpp:149
#62 0x00007ffff3714578 in QEventLoop::exec (this=0x7fffffffde20, flags=...) at kernel/qeventloop.cpp:204
#63 0x00007ffff3719738 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1187
#64 0x00007ffff7b89677 in kdemain (argc=1, argv=0x7fffffffe098) at ../../../dolphin/src/main.cpp:90
---Type <return> to continue, or q <return> to quit---
#65 0x00007ffff779c76d in __libc_start_main (main=0x4006a0 <main(int, char**)>, argc=1, ubp_av=0x7fffffffe098, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, 
    stack_end=0x7fffffffe088) at libc-start.c:226
#66 0x00000000004006d1 in _start ()

I checked with activities. I do not actively use them and I also could not find any service-menus related to them.

Sometimes I wonder why I take the time to write detailed comments if nobody cares to read the details anyway...

*** This bug has been marked as a duplicate of bug 314575 ***

(In reply to comment #5)
> I checked with activities. I do not actively use them and I also could not
> find any service-menus related to them.

But the backtrace contains a KActivities function, sorry if that wasn't obvious to you. And yes, there is a "Link to activity" service or something like that (can't check right now what the exact name is).