GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please try to obtain a backtrace following the instructions at http://wiki.ubuntu.com/DebuggingProgramCrash and upload the backtrace (as an attachment) to the bug report. This will greatly help us in tracking down your problem.

I also get the same error when running rhythmbox, I also have a UbuntuOne Music Store plugin tick open, over here: https://bugs.launchpad.net/rhythmbox-ubuntuone-music-store/+bug/629792

In general, it took me a WHILE before I realized that number after rhythmbox is the Process ID number of RB; and not like some sort of line number in the source somehow. But I also get the error messages the OP posted, except just one assertion error and the sinkfunc warning after it, not multiples of the same message. A backtrace I don't beleive is possible since, the errors come up upon loading RB, which it does fully load, meaning: there's stopping point at which you can tell gdb to "bt" since there's not really anywhere to backtrace from. I did try to compile the source, (It's been a little over a week; was hoping it'd be fixed by now -- either way, my memory is a little hazy), but I think it did compile and install properly. Just no joy. Inside of RB I get import errors for mp3 demuxer's once RB has loaded. I dunno.. *shrug* I don't know what this thing's problem is. All I know is, I have nothing but problems with this music player. (I know, that last bit was unneeded; it is true though. You should've seen the the paragraph rant I removed on configure's use of the >= rule for library versions)

The sentence: "A backtrace I don't beleive is possible since, the errors come up upon loading RB, which it does fully load, meaning: there's stopping point at which you can tell gdb to "bt" since there's not really anywhere to backtrace from."

should have been written to say "<...> there's no stopping point <...>"

I didn't know you could ctr+c in gdb and still get a backtrace. I went back to the debugging pages to see if there was some way some how to get a backtrace, I think this'll suffice. I read in the instructions that if a program hangs but doesn't crash you can perform a ctrl+c and still get a backtrace. I took a non-hanging (but responding to input) as if it were a program hanging and did just that (the ctrl+c). Sure enough I was able to get a backtrace. Hopefully it's detailed enough, since the conditions fall outside the normal. I'm attaching the log to my reply.

could you please get another backtrace? the one submitted doesn't contain any related symbols.

That's weird, I really thought I had symbols installed, let me try running through the process again. Ok prior to running it, I went to the https://wiki.ubuntu.com/DebuggingProgramCrash page instead of skipping like I did the last time and just going straight to https://wiki.ubuntu.com/Backtrace ... I ran the command that checks for symbol packages installed and it does list:

i rhythmbox-dbg - debugging symbols for rhythmbox

amoung a bunch of other dbg packages. After knowing this I skipped the rest of the DebuggingProgramCrash page as it basically just talked about installing dbg packages (Which I already apparently have installed) and used Yelp as an example. All this is extra information I know, just I wanted to establish a baseline as I perform the backtrace again.

So now at this point I'm going back to the backtrace page and rerunning through the process after having confirmed the dbg package installed.

Please note, the program runs, so there is no hanging or crashing occuring, so the only way I'm able to get a stack trace is by hitting ctrl+c once the RB is up; which makes me think any backtrace I get is going to be useless since the error occurs as it's loading and does not in any way prevent the program from actually coming up. So I'm not sure what to do about that, but here is the (Attached) backtrace nonetheless. Let me know if there's anything else I can provide or try.

This bugs affecting my system to. When I try to use the Magnatune plugin it says:

GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed

I don't know if this is related, but running rb in debugger causes this:

(15:22:15) [0x8050e68] [construct_sources] rb-shell.c:1450: shell: creating playlist manager
(15:22:15) [0x8050e68] [construct_sources] rb-shell.c:1464: shell: creating removable media manager
(15:22:15) [0x8050e68] [construct_load_ui] rb-shell.c:1485: shell: loading ui
(15:22:15) [0x834cfb0] [query_thread_main] rhythmdb.c:4020: entering query thread
(15:22:15) [0x834cfb0] [rhythmdb_query_internal] rhythmdb.c:3997: doing query
(15:22:15) [0x834cfb0] [do_query_recurse] rhythmdb-tree.c:2301: doing recursive query, 1 conjunctions
(15:22:15) [0x834cfb0] [rhythmdb_query_model_add_results] rhythmdb-query-model.c:2248: adding 0 entries
(15:22:15) [0x834cfb0] [rhythmdb_query_internal] rhythmdb.c:4003: completed
(15:22:15) [0x8050e68] [rb_shell_select_source] rb-shell.c:2201: selecting source 0x832e0b8
(15:22:15) [0x8050e68] [rb_shell_clipboard_set_source_internal] rb-shell-clipboard.c:354: selected source 0x832e0b8
(15:22:15) [0x8050e68] [rb_shell_clipboard_sync] rb-shell-clipboard.c:600: syncing clipboard
(15:22:15) [0x8050e68] [rebuild_playlist_menu] rb-shell-clipboard.c:1036: rebuilding add-to-playlist menu

(rhythmbox:16261): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed

Program received signal SIGINT, Interrupt.
0xb7fe2832 in ?? () from /lib/ld-linux.so.2
(gdb) bt
#0 0xb7fe2832 in ?? () from /lib/ld-linux.so.2
#1 0xb73a4990 in raise () from /lib/libpthread.so.0
#2 0xb7f6b599 in rb_debug_stop_in_debugger () at rb-debug.c:255
#3 0xb7f6b601 in log_handler (domain=0xb7389ecc "GLib-GObject", level=G_LOG_LEVEL_CRITICAL,
    message=0x83a6348 "g_object_unref: assertion `G_IS_OBJECT (object)' failed", data=0x0) at rb-debug.c:272
#4 0xb72be0eb in g_logv () from /lib/libglib-2.0.so.0
#5 0xb72be572 in g_log () from /lib/libglib-2.0.so.0
#6 0xb72be79d in g_return_if_fail_warning () from /lib/libglib-2.0.so.0
#7 0xb73614e2 in g_object_unref () from /usr/lib/libgobject-2.0.so.0
#8 0xb7edc614 in add_playlist_to_menu (model=0x820b438, path=0x825c0a8, iter=0xbfffee30, clipboard=0x81f49b0) at rb-shell-clipboard.c:982
#9 0xb7c8b4e0 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#10 0xb7c8b521 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#11 0xb7c8bccb in gtk_tree_model_foreach () from /usr/lib/libgtk-x11-2.0.so.0
#12 0xb7edbe9b in rebuild_playlist_menu (clipboard=0x820b438) at rb-shell-clipboard.c:1056
#13 0xb7edc203 in rb_shell_clipboard_set_property (object=0x81f49b0, prop_id=1, value=0xbffff008, pspec=0x8204990) at rb-shell-clipboard.c:453
#14 0xb736595a in g_object_set_valist () from /usr/lib/libgobject-2.0.so.0
#15 0xb7366076 in g_object_set () from /usr/lib/libgobject-2.0.so.0
#16 0xb7edabb6 in rb_shell_clipboard_set_source (clipboard=0x81f49b0, source=0x832e0b8) at rb-shell-clipboard.c:532
#17 0xb7ed2510 in rb_shell_select_source (shell=0x8209010, source=0x832e0b8) at rb-shell.c:2225
#18 0xb7ed9ba8 in rb_shell_constructed (object=0x8209010) at rb-shell.c:1633
#19 0xb7364a2c in g_object_newv () from /usr/lib/libgobject-2.0.so.0
#20 0xb73653cc in g_object_new_valist () from /usr/lib/libgobject-2.0.so.0
#21 0xb73654e7 in g_object_new () from /usr...

I get two of these errors; unsure if it's what is preventing RB from playing any of my music:

(10:48:09) [0x1ede040] [rb_display_page_model_add_page] rb-display-page-model.c:618: inserting source New Downloads with parent 0x20eeae0
(10:48:09) [0x1ede040] [rb_find_user_file] rb-file-helpers.c:224: found user dir path for 'playlists.xml': /home/jameson/.local/share/rhythmbox/playlists.xml
(10:48:09) [0x1ede040] [construct_sources] rb-shell.c:1448: shell: creating playlist manager
(10:48:09) [0x1ede040] [construct_sources] rb-shell.c:1464: shell: creating removable media manager
(10:48:09) [0x1ede040] [construct_load_ui] rb-shell.c:1485: shell: loading ui
(10:48:09) [0x1ede040] [rb_shell_select_page] rb-shell.c:2197: selecting page 0x2328010
(10:48:09) [0x1ede040] [rb_shell_clipboard_set_source_internal] rb-shell-clipboard.c:354: selected source 0x2328010
(10:48:09) [0x1ede040] [rb_shell_clipboard_sync] rb-shell-clipboard.c:600: syncing clipboard
(10:48:09) [0x1ede040] [rebuild_playlist_menu] rb-shell-clipboard.c:1035: rebuilding add-to-playlist menu

(rhythmbox:9786): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed
(10:48:09) [0x1ede040] [rb_shell_player_set_source_internal] rb-shell-player.c:1108: selected source 0x2328010
(10:48:09) [0x1ede040] [rb_shell_player_sync_with_selected_source] rb-shell-player.c:3440: syncing with selected source: 0x2328010
(10:48:09) [0x1ede040] [rb_shell_player_sync_with_selected_source] rb-shell-player.c:3443: no playing source, new source is 0x2328010
(10:48:09) [0x1ede040] [rb_shell_player_sync_with_source] rb-shell-player.c:2966: playing source: (nil), active entry: (nil)
(10:48:09) [0x1ede040] [rb_shell_set_window_title] rb-shell.c:2259: clearing title

and

(10:48:13) [0x1ede040] [rb_property_view_selection_changed_cb] rb-property-view.c:838: selection changed
(10:48:13) [0x1ede040] [rb_property_view_selection_changed_cb] rb-property-view.c:838: selection changed
(10:48:13) [0x1ede040] [rb_property_view_selection_changed_cb] rb-property-view.c:838: selection changed
(10:48:13) [0x1ede040] [rebuild_playlist_menu] rb-shell-clipboard.c:1035: rebuilding add-to-playlist menu

(rhythmbox:9786): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed
(10:48:13) [0x1ede040] [rb_shell_clipboard_entryview_changed_cb] rb-shell-clipboard.c:809: entryview changed
(10:48:13) [0x1ede040] [rb_shell_clipboard_sync] rb-shell-clipboard.c:600: syncing clipboard
(10:48:13) [0x1ede040] [rb_browser_source_state_pref_changed] rb-browser-source.c:750: state prefs changed
(10:48:13) [0x1ede040] [rb_browser_source_state_prefs_sync] rb-browser-source.c:760: syncing state

Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to look at all reported bugs in a timely manner. There have been many changes in Ubuntu since that time you reported the bug and your problem may have been fixed with some of the updates. It would help us a lot if you could test it on a currently supported Ubuntu version. When you test it and it is still an issue, kindly upload the updated logs by running apport-collect <bug #> and any other logs that are relevant for this particular issue.

[Expired for rhythmbox (Ubuntu) because there has been no activity for 60 days.]