Your screenshot looks like Yosemite, is that right? We can see if we have anything useful in the log files.
Open Finder, and select the "Go" menu at the top of the screen. Hold the Option key, and select the "Library" menu option from the Go menu. (On OSX Lion and above, Library will only appear with the Option key held.)
From Library, navigate to Logs -> DeviceLink.
In that DeviceLink folder, hopefully you'll see a log file titled starting with "AppleMobileBackup" that's likely to be the most helpful log. There might be something of interest in there. Here's a glance at mine, so we can see what is semi-normal 😉 and because I believe in posting what I ask others to post.
2014-12-05 11:39:31.671|AppleMobileBackup|1385:2060833552|DeviceLinkConnection.c:_DLMainTh readMessagePortCallback| ERROR: Error creating components from read data: 'NULL data returned from read'
2014-12-05 11:39:31.672|AppleMobileBackup|1385:63442944|SocketStreamHandler.c:_SocketLogCa llback| ERROR: SocketSend (data): error 32: Broken pipe
2014-12-05 11:39:31.672|AppleMobileBackup|1385:63442944|StreamHandler.c:_WriteFunc| ERROR: Error sending data: Can't send data
2014-12-05 11:39:31.672|AppleMobileBackup|1385:63442944|DeviceLinkConnection.c:_DLHandlerT hreadMessagePortCallback| ERROR: Could not send disconnect message: 'Error writing length of data'
2014-12-05 11:40:11.370|AppleMobileBackup|1399:85463040|SocketStreamHandler.c:_SocketLogCa llback| ERROR: SocketRecv (data): return of 0 bytes
2014-12-05 11:40:11.370|AppleMobileBackup|1399:85463040|StreamHandler.c:_ReadFunc| ERROR: Error reading data: Can't read data
2014-12-05 11:40:11.370|AppleMobileBackup|1399:85463040|DeviceLinkConnection.c:_DLHandlerT hreadReadMessage| ERROR: Could not receive message: '(null)'
2014-12-05 11:40:11.370|AppleMobileBackup|1399:2060833552|DeviceLinkConnection.c:_DLMainTh readMessagePortCallback| ERROR: Error creating components from read data: 'NULL data returned from read'
2014-12-05 11:40:11.371|AppleMobileBackup|1399:85463040|SocketStreamHandler.c:_SocketLogCa llback| ERROR: SocketSend (data): error 32: Broken pipe
2014-12-05 11:40:11.371|AppleMobileBackup|1399:85463040|StreamHandler.c:_WriteFunc| ERROR: Error sending data: Can't send data
2014-12-05 11:40:11.371|AppleMobileBackup|1399:85463040|DeviceLinkConnection.c:_DLHandlerT hreadMessagePortCallback| ERROR: Could not send disconnect message: 'Error writing length of data'
2014-12-05 11:42:57.718|AppleMobileBackup|1417:2060833552|DeviceLinkConnection.c:_DLMainTh readMessagePortCallback| ERROR: Error creating components from read data: 'NULL data returned from read'
2014-12-05 11:44:38.880|AppleMobileBackup|1444:2060833552|DeviceLinkConnection.c:_DLMainTh readMessagePortCallback| ERROR: Error creating components from read data: 'NULL data returned from read'
2014-12-05 11:46:07.331|AppleMobileBackup|1449:2060833552|DeviceLinkConnection.c:_DLMainTh readMessagePortCallback| ERROR: Error creating components from read data: 'NULL data returned from read'