Also can't connect to Samba shares.
In 10.9.4 the error was a PreXP / deprecated error in the Console log, as I was connecting to Windows 98 share.
I was able to access my smb share by using MuCommander, and copy files from Win98 to Mavericks 10.9.4.
MuCommander doesn't properly copy files the other way however. Files are transferred back with blank created and modified dates, and PDFs are copying back with images corrupted. Thus, this isn't a perfect solution.
10.9.5 is now out, with improved Samba / SMB connections.
I just upgraded.
Now, the PreXP/depreciation error is no more!
I've got a NEW error:
NetAuthSysAgent[274]: doConnectWithTimeout: nb_sockapi_connect failed, errno=61 Connection refused
I just tried using the commander line connection method also:
/sbin/mount_smbfs
(which is explained here: http://forums.macrumors.com/showpost.php?p=13022967&postcount=9 )
....and that gives me the original error in the console log:
kernel[0]: smb1_smb_negotiate: Support for the server UG has been deprecated (PreXP), disconnecting
So either I need MuCommander to actually transfer files with a created and modified date.
Or I need to solve the Finder's Samba errors, =P.
For now, I'll just use my old G4 as a go-between, and connect to my Samba share via the G4, copy files to the G4, and then have Mavericks connect to the G4 via Apple File Sharing to get the files.