What do you think of this? I believed this occurred when I tried to drag and drop and .jpg into a new mail message. (I removed my username where needed):

1/16/15 3:15:18 PM Mail[108] *** WebKit discarding exception: <NSRangeException> *** -[NSCFArray objectAtIndex:]: index (0) beyond bounds (0)

1/16/15 3:15:29 PM Mail[108] Error writing to /Users/myusername/Library/Mail/RSS/.mboxCache.plist: Error Domain=NSCocoaErrorDomain Code=4 UserInfo=0x10b623190 "The folder “RSS” doesn’t exist." Underlying Error=(Error Domain=NSPOSIXErrorDomain Code=2 "The operation couldn’t be completed. No such file or directory")

I'm also getting this:

1/16/15 3:11:29 PM ReportCrash[113] Saved crash report for LCCDaemon[103] version 3.5.1 (3.5.1) to /Users/myusername/Library/Logs/DiagnosticReports/LCCDaemon_2015-01-16-151129_Macintosh.crash

LCCDaemon is, I assume, related to the Logitech Control Center for my mouse. I've already tried uninstalling it to see if that makes a difference but it doesn't. I'm not sure why the word "crash" is used when my Mac didn't crash.