Also, I tried running these instructions on a fresh Lubuntu virtual machine, and got these errors when I tried to launch monodevelop-stable:
ERROR [2017-04-01 13:41:21Z]: Failed to redirect output to log file
System.UnauthorizedAccessException: Access to the path "/home/josh/.cache/MonoDevelop-6.0/Logs" is denied.
at System.IO.Directory.CreateDirectoriesInternal (System.String path) [0x00070] in <f712f98eb8e445c8918edaf595bbe465>:0
at System.IO.Directory.CreateDirectory (System.String path) [0x000a4] in <f712f98eb8e445c8918edaf595bbe465>:0
at MonoDevelop.Core.LoggingService.RedirectOutputToFileUnix () [0x00012] in <ecded49933f54915a63b93f09319c157>:0
at MonoDevelop.Core.LoggingService.RedirectOutputToLogFile () [0x00019] in <ecded49933f54915a63b93f09319c157>:0
INFO [2017-04-01 13:41:22Z]: Starting MonoDevelop 6.2
INFO [2017-04-01 13:41:22Z]: Running on Mono 4.8.0 (Stable 4.8.0.520/8f6d0f6 Wed Mar 15 16:18:35 UTC 2017) (64-bit)
INFO [2017-04-01 13:41:22Z]: Operating System: Linux
Linux lubvm 4.8.0-22-generic #24-Ubuntu SMP Sat Oct 8 09:15:00 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
INFO [2017-04-01 13:41:22Z]: Using GTK+ 2.24.30
System.UnauthorizedAccessException: Access to the path "/home/josh/.cache/MonoDevelop-6.0/addin-db-002/hosts/MonoDevelop.addins" is denied.
at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean anonymous, System.IO.FileOptions options) [0x0025f] in <f712f98eb8e445c8918edaf595bbe465>:0
at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.IO.FileOptions options, System.String msgPath, System.Boolean bFromProxy, System.Boolean useLongPath, System.Boolean checkHost) [0x00000] in <f712f98eb8e445c8918edaf595bbe465>:0
at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare,int,System.IO.FileOptions,string,bool,bool,bool)
at System.IO.StreamWriter.CreateFile (System.String path, System.Boolean append, System.Boolean checkHost) [0x00022] in <f712f98eb8e445c8918edaf595bbe465>:0
at System.IO.StreamWriter..ctor (System.String path, System.Boolean append, System.Text.Encoding encoding, System.Int32 bufferSize, System.Boolean checkHost) [0x00061] in <f712f98eb8e445c8918edaf595bbe465>:0
at System.IO.StreamWriter..ctor (System.String path, System.Boolean append, System.Text.Encoding encoding, System.Int32 bufferSize) [0x00000] in <f712f98eb8e445c8918edaf595bbe465>:0
at System.IO.StreamWriter..ctor (System.String path) [0x00008] in <f712f98eb8e445c8918edaf595bbe465>:0
at (wrapper remoting-invoke-with-check) System.IO.StreamWriter:.ctor (string)
at Mono.Addins.AddinRegistry.CreateHostAddinsFile (System.String hostFile) [0x00142] in <bd16ebf525e04bea9f1e0907860e61de>:0
at Mono.Addins.AddinEngine.Initialize (System.Reflection.Assembly startupAsm, System.String configDir, System.String addinsDir, System.String databaseDir) [0x0009f] in <bd16ebf525e04bea9f1e0907860e61de>:0
at Mono.Addins.AddinManager.Initialize (System.String configDir, System.String addinsDir, System.String databaseDir) [0x0001e] in <bd16ebf525e04bea9f1e0907860e61de>:0
at MonoDevelop.Core.Runtime.Initialize (System.Boolean updateAddinRegistry) [0x00110] in <ecded49933f54915a63b93f09319c157>:0
INFO [2017-04-01 13:41:23Z]: GTK: Using Gtk theme from /usr/share/themes/Lubuntu-default
Starting MonoDevelop
FATAL ERROR [2017-04-01 13:41:23Z]: MonoDevelop failed to start. Some of the assemblies required to run MonoDevelop (for example gtk-sharp)may not be properly installed in the GAC.
System.InvalidOperationException: Add-in engine not initialized.
at Mono.Addins.AddinEngine.CheckInitialized () [0x0000c] in <bd16ebf525e04bea9f1e0907860e61de>:0
at Mono.Addins.AddinManager.GetExtensionObjects (System.String path) [0x00006] in <bd16ebf525e04bea9f1e0907860e61de>:0
at MonoDevelop.Ide.DesktopService.Initialize () [0x00010] in <8e60aa0560c44ca69e4f561f2f540933>:0
at MonoDevelop.Ide.IdeStartup.Run (MonoDevelop.Ide.MonoDevelopOptions options) [0x00332] in <8e60aa0560c44ca69e4f561f2f540933>:0
at MonoDevelop.Ide.IdeStartup.Main (System.String[] args, MonoDevelop.Ide.Extensions.IdeCustomizer customizer) [0x000ab] in <8e60aa0560c44ca69e4f561f2f540933>:0