This is also happening to me, Tomboy will crash several times a day. This only started happening to me after I upgraded to 11.10 I have started it from the command line with --debug but the funny thing is that it doesn't crash anymore but I get this error "Error saving note" and it mentions disk space and permissions, still have plenty of disk save and permissions are fine as the notes will save most of the time. Below is the debug output: ** Running Mono with --debug ** [DEBUG 20:30:56.191] NoteManager created with note path "/home/angus/.local/share/tomboy". [INFO 20:30:56.771] Initializing Mono.Addins [DEBUG 20:30:57.022] AddinManager.OnAddinLoaded: Tomboy.Tomboy [DEBUG 20:30:57.024] Name: Tomboy.Tomboy,0.10 [DEBUG 20:30:57.024] Description: [DEBUG 20:30:57.024] Namespace: Tomboy [DEBUG 20:30:57.024] Enabled: True [DEBUG 20:30:57.024] File: /usr/lib/tomboy/Tomboy.exe [DEBUG 20:30:57.918] AddinManager.OnAddinLoaded: Tomboy.ExportToHtmlAddin [DEBUG 20:30:57.918] Name: Export to HTML [DEBUG 20:30:57.918] Description: Exports individual notes to HTML. [DEBUG 20:30:57.918] Namespace: Tomboy [DEBUG 20:30:57.918] Enabled: True [DEBUG 20:30:57.918] File: /usr/lib/tomboy/addins/ExportToHtml.dll [DEBUG 20:30:57.921] AddinManager.OnAddinLoaded: Tomboy.WebDavSyncServiceAddin [DEBUG 20:30:57.921] Name: WebDav Sync Service Add-in [DEBUG 20:30:57.921] Description: Synchronize Tomboy Notes to a WebDav URL [DEBUG 20:30:57.921] Namespace: Tomboy [DEBUG 20:30:57.921] Enabled: True [DEBUG 20:30:57.921] File: /usr/lib/tomboy/addins/WebDavSyncService.dll [DEBUG 20:30:57.924] Unable to locate 'gnomesu' in your PATH [DEBUG 20:30:57.924] Using '/usr/bin/gksu' as GUI 'su' tool [DEBUG 20:30:57.924] Successfully found all system tools [DEBUG 20:30:57.924] Unable to locate 'wdfs' in your PATH [DEBUG 20:30:57.924] AddinManager.OnAddinLoaded: Tomboy.WebSyncServiceAddin [DEBUG 20:30:57.924] Name: Web Sync Service Add-in [DEBUG 20:30:57.924] Description: Synchronize Tomboy Notes with Tomboy Online and other compatible web services [DEBUG 20:30:57.924] Namespace: Tomboy [DEBUG 20:30:57.924] Enabled: True [DEBUG 20:30:57.924] File: /usr/lib/tomboy/addins/WebSyncServiceAddin.dll [DEBUG 20:30:57.925] AddinManager.OnAddinLoaded: Tomboy.FileSystemSyncServiceAddin [DEBUG 20:30:57.926] Name: Local Directory Sync Service Add-in [DEBUG 20:30:57.926] Description: Synchronize Tomboy Notes to a local file system path [DEBUG 20:30:57.926] Namespace: Tomboy [DEBUG 20:30:57.926] Enabled: True [DEBUG 20:30:57.926] File: /usr/lib/tomboy/addins/FileSystemSyncService.dll [DEBUG 20:30:57.929] Loading notes [DEBUG 20:30:58.696] AddinManager.OnAddinLoaded: Tomboy.PrintNotesAddin [DEBUG 20:30:58.696] Name: Printing Support [DEBUG 20:30:58.696] Description: Allows you to print a note. [DEBUG 20:30:58.696] Namespace: Tomboy [DEBUG 20:30:58.696] Enabled: True [DEBUG 20:30:58.696] File: /usr/lib/tomboy/addins/PrintNotes.dll [DEBUG 20:30:58.697] AddinManager.OnAddinLoaded: Tomboy.BacklinksAddin [DEBUG 20:30:58.697] Name: Backlinks [DEBUG 20:30:58.697] Description: See which notes link to the one you're currently viewing. [DEBUG 20:30:58.697] Namespace: Tomboy [DEBUG 20:30:58.697] Enabled: True [DEBUG 20:30:58.697] File: /usr/lib/tomboy/addins/Backlinks.dll [DEBUG 20:30:58.698] AddinManager.OnAddinLoaded: Tomboy.StickyNoteImportAddin [DEBUG 20:30:58.698] Name: Sticky Notes Importer [DEBUG 20:30:58.698] Description: Import your notes from the Sticky Notes applet. [DEBUG 20:30:58.698] Namespace: Tomboy [DEBUG 20:30:58.698] Enabled: True [DEBUG 20:30:58.698] File: /usr/lib/tomboy/addins/StickyNoteImport.dll [DEBUG 20:30:58.699] StickyNoteImporter: Sticky Notes XML file does not exist or is invalid! [DEBUG 20:30:58.699] AddinManager.OnAddinLoaded: Tomboy.EvolutionAddin [DEBUG 20:30:58.699] Name: Evolution Mail Integration [DEBUG 20:30:58.699] Description: Allows you to drag an email from Evolution into a Tomboy note. The message subject is added as a link in the note with an envelope icon next to it. [DEBUG 20:30:58.699] Namespace: Tomboy [DEBUG 20:30:58.699] Enabled: True [DEBUG 20:30:58.699] File: /usr/lib/tomboy/addins/Evolution.dll [DEBUG 20:30:58.755] AddinManager.OnAddinLoaded: Tomboy.FixedWidthAddin [DEBUG 20:30:58.755] Name: Fixed Width [DEBUG 20:30:58.756] Description: Adds fixed-width font style. [DEBUG 20:30:58.756] Namespace: Tomboy [DEBUG 20:30:58.756] Enabled: True [DEBUG 20:30:58.756] File: /usr/lib/tomboy/addins/FixedWidth.dll [DEBUG 20:30:58.868] Unable to locate 'wdfs' in your PATH [DEBUG 20:30:58.932] Autosync pref changed...restarting sync timer [DEBUG 20:30:58.966] Tomboy remote control active. [DEBUG 20:32:31.056] Loading notebooks [DEBUG 20:32:39.845] Creating Buffer for 'SIRF Alarm system and Procedure'... [DEBUG 20:32:40.001] SIRF Alarm system and Procedure tags: [DEBUG 20:32:46.399] Saving 'SIRF Alarm system and Procedure'... [DEBUG 20:32:54.922] Saving 'SIRF Alarm system and Procedure'... [DEBUG 20:33:09.030] Creating Buffer for 'SIRF - Pilot Line'... [DEBUG 20:33:09.072] SIRF - Pilot Line tags: [DEBUG 20:33:13.134] Saving 'SIRF - Pilot Line'... [DEBUG 20:33:23.034] Saving 'SIRF - Pilot Line'... [DEBUG 20:33:31.173] Saving 'SIRF - Pilot Line'... [DEBUG 20:33:46.960] Saving 'SIRF - Pilot Line'... [DEBUG 20:34:52.556] Saving 'SIRF - Pilot Line'... [DEBUG 20:35:02.382] Saving 'SIRF - Pilot Line'... [DEBUG 20:35:13.348] Saving 'SIRF - Pilot Line'... [DEBUG 20:35:52.474] Saving 'SIRF - Pilot Line'... [DEBUG 20:36:29.083] Saving 'SIRF - Pilot Line'... [DEBUG 20:37:07.915] Saving 'SIRF - Pilot Line'... [DEBUG 20:37:38.296] Saving 'SIRF - Pilot Line'... [DEBUG 20:38:05.386] Saving 'SIRF - Pilot Line'... [DEBUG 20:38:36.709] Saving 'SIRF - Pilot Line'... [DEBUG 20:39:17.265] Saving 'SIRF - Pilot Line'... [DEBUG 20:40:01.607] Note edited...killing autosync timer until next save or delete event [DEBUG 20:40:05.616] Saving 'SIRF - Pilot Line'... [DEBUG 20:40:05.709] Note saved or deleted...restarting sync timer [DEBUG 20:41:06.253] BackgroundSyncChecker: Checking server for updates [DEBUG 20:41:06.257] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/ [DEBUG 20:41:14.708] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/user/ [DEBUG 20:41:16.806] BackgroundSyncChecker: Detected that sync would be a good idea now [DEBUG 20:41:16.816] SyncThread using SyncServiceAddin: Tomboy Web [DEBUG 20:41:16.817] SilentUI: SyncStateChanged: Connecting [DEBUG 20:41:16.824] SilentUI: SyncStateChanged: AcquiringLock [DEBUG 20:41:16.826] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/ [DEBUG 20:41:17.381] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/user/ [DEBUG 20:41:18.151] 8 [DEBUG 20:41:18.152] SilentUI: SyncStateChanged: PrepareDownload [DEBUG 20:41:18.153] Sync: GetNoteUpdatesSince rev 502 [DEBUG 20:41:18.156] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/op/?include_notes=true&since=502 [DEBUG 20:41:18.922] Sync: 0 updates since rev 502 [DEBUG 20:41:18.926] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/op/ [DEBUG 20:41:22.340] SilentUI: SyncStateChanged: PrepareUpload [DEBUG 20:41:22.341] Saving 'SIRF - Pilot Line'... [DEBUG 20:41:22.358] Saving 'SIRF Alarm system and Procedure'... [DEBUG 20:41:22.341] Saving 'SIRF - Pilot Line'... [DEBUG 20:41:22.375] SilentUI: NoteSynchronized, Title: SIRF - Pilot Line, Type: UploadModified [DEBUG 20:41:22.375] Saving 'SIRF Alarm system and Procedure'... [ERROR 20:41:22.382] Synchronization failed with the following exception: Collection was modified; enumeration operation may not execute. at System.Collections.Generic.List`1+Enumerator[Tomboy.Note].VerifyState () [0x00000] in :0 at System.Collections.Generic.List`1+Enumerator[Tomboy.Note].MoveNext () [0x00000] in :0 at Tomboy.NoteRecentChanges.UpdateResults () [0x00000] in :0 at Tomboy.NoteRecentChanges.OnNoteSaved (Tomboy.Note note) [0x00000] in :0 at (wrapper delegate-invoke) :invoke_void__this___Note (Tomboy.Note) at Tomboy.NoteManager.OnNoteSave (Tomboy.Note note) [0x00000] in :0 at Tomboy.Note.Save () [0x00000] in :0 at Tomboy.Sync.SyncManager.SynchronizationThread () [0x00000] in :0 [DEBUG 20:41:22.382] SilentUI: SyncStateChanged: Idle [DEBUG 20:41:22.386] SilentUI: SyncStateChanged: Failed [DEBUG 20:41:22.386] SilentUI: SyncStateChanged: Idle [DEBUG 20:42:08.739] Saving 'SIRF - Pilot Line'... [DEBUG 20:44:22.995] Saving 'SIRF - Pilot Line'... [DEBUG 20:44:30.458] Saving 'SIRF - Pilot Line'... [DEBUG 20:44:39.358] Saving 'SIRF - Pilot Line'... [DEBUG 20:44:53.551] Saving 'SIRF - Pilot Line'... [DEBUG 20:45:05.506] Saving 'SIRF - Pilot Line'... [DEBUG 20:45:15.777] Saving 'SIRF - Pilot Line'... [DEBUG 20:45:25.858] Saving 'SIRF - Pilot Line'... [DEBUG 20:45:46.029] Saving 'SIRF - Pilot Line'... [DEBUG 20:46:20.537] Saving 'SIRF - Pilot Line'... [DEBUG 20:46:41.177] Saving 'SIRF - Pilot Line'... [DEBUG 20:47:09.513] Saving 'SIRF - Pilot Line'... [DEBUG 20:47:25.979] Saving 'SIRF - Pilot Line'... [DEBUG 20:48:48.792] Saving 'SIRF - Pilot Line'... [DEBUG 20:51:05.714] BackgroundSyncChecker: Checking server for updates [DEBUG 20:51:05.714] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/ [DEBUG 20:51:09.742] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/user/ [DEBUG 20:51:12.196] BackgroundSyncChecker: Detected that sync would be a good idea now [DEBUG 20:51:12.197] SyncThread using SyncServiceAddin: Tomboy Web [DEBUG 20:51:12.198] SilentUI: SyncStateChanged: Connecting [DEBUG 20:51:12.202] SilentUI: SyncStateChanged: AcquiringLock [DEBUG 20:51:12.203] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/ [DEBUG 20:51:12.796] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/user/ [DEBUG 20:51:13.579] 8 [DEBUG 20:51:13.579] SilentUI: SyncStateChanged: PrepareDownload [DEBUG 20:51:13.580] Sync: GetNoteUpdatesSince rev 502 [DEBUG 20:51:13.580] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/op/?include_notes=true&since=502 [DEBUG 20:51:14.283] Sync: 0 updates since rev 502 [DEBUG 20:51:14.284] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/op/ [DEBUG 20:51:16.898] SilentUI: SyncStateChanged: PrepareUpload [DEBUG 20:51:16.898] Saving 'SIRF - Pilot Line'... [DEBUG 20:51:16.902] Saving 'SIRF - Pilot Line'... [DEBUG 20:51:16.913] SilentUI: NoteSynchronized, Title: SIRF - Pilot Line, Type: UploadModified [ERROR 20:51:16.913] Error while saving: System.InvalidOperationException: Collection was modified; enumeration operation may not execute. at System.Collections.Generic.List`1+Enumerator[Tomboy.Note].VerifyState () [0x00000] in :0 at System.Collections.Generic.List`1+Enumerator[Tomboy.Note].MoveNext () [0x00000] in :0 at Tomboy.NoteRecentChanges.UpdateResults () [0x00000] in :0 at Tomboy.NoteRecentChanges.OnNoteSaved (Tomboy.Note note) [0x00000] in :0 at (wrapper delegate-invoke) :invoke_void__this___Note (Tomboy.Note) at Tomboy.NoteManager.OnNoteSave (Tomboy.Note note) [0x00000] in :0 at Tomboy.Note.Save () [0x00000] in :0 at Tomboy.Note.SaveTimeout (System.Object sender, System.EventArgs args) [0x00000] in :0 [DEBUG 20:51:16.913] Saving 'SIRF Alarm system and Procedure'... [DEBUG 20:51:16.914] Saving 'SIRF Alarm system and Procedure'... [ERROR 20:51:16.915] Exception while saving note: System.IO.IOException: Sharing violation on path /home/angus/.local/share/tomboy/894bd4fb-f3b4-433c-acc2-1997205f513e.note.tmp at System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) [0x00000] in :0 at System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share) [0x00000] in :0 at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare) at System.IO.StreamWriter..ctor (System.String path, Boolean append, System.Text.Encoding encoding, Int32 bufferSize) [0x00000] in :0 at System.IO.StreamWriter..ctor (System.String path, Boolean append, System.Text.Encoding encoding) [0x00000] in :0 at (wrapper remoting-invoke-with-check) System.IO.StreamWriter:.ctor (string,bool,System.Text.Encoding) at System.Xml.XmlWriter.Create (System.String file, System.Xml.XmlWriterSettings settings) [0x00000] in :0 at Tomboy.NoteArchiver.WriteFile (System.String write_file, Tomboy.NoteData note) [0x00000] in :0 at Tomboy.NoteArchiver.Write (System.String write_file, Tomboy.NoteData note) [0x00000] in :0 at Tomboy.Note.Save () [0x00000] in :0 [DEBUG 20:51:16.935] SilentUI: NoteSynchronized, Title: SIRF Alarm system and Procedure, Type: UploadModified [DEBUG 20:51:16.935] Sync: Uploading 2 note updates [DEBUG 20:51:16.935] SilentUI: SyncStateChanged: Uploading [DEBUG 20:51:16.990] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/op/ [DEBUG 20:51:19.717] SilentUI: SyncStateChanged: CommittingChanges [DEBUG 20:51:19.732] Building web request for URL: https://one.ubuntu.com/notes/api/1.0/op/ [DEBUG 20:51:21.297] SilentUI: SyncStateChanged: Succeeded [DEBUG 20:51:21.300] Sync: New revision: 503 [DEBUG 20:51:21.300] SilentUI: SyncStateChanged: Idle