Finally I found a Technet discussion on the issue, which correctly identified an incorrect registry value HPTrayCount which is set to 0 when the printer driver is changed, but is not set back to a working value.

This value needs to be changed to 0×12 (decimal 18) for each HP printer for it to work correctly. However, on print servers with lots of HP printers this can be very time consuming. To speed this process I have written the vbscript below which will check if the value exists for each printer, and if it is set to 0 will set it to 0×12.

' For each Printer in Registry check if HPTrayCount exists and is set to 0, then set to 12

'http://social.technet.microsoft.com/Forums/en/winserverprint/thread/5101195b-3aca-4699-9a06-db4578614e2d

strKeyPath = "SOFTWARE\Microsoft\Windows NT\CurrentVersion\Print\Printers"
strValueName = "HPTrayCount"
inHPValue = 18 ' Is equal to Hex 12, makesprinter driver work.

'http://www.activexperts.com/activmonitor/windowsmanagement/adminscripts/registry/#EnumRegVals.htm
const HKEY_LOCAL_MACHINE = &H80000002
strComputer = "."
Set StdOut = WScript.StdOut

Set oReg=GetObject("winmgmts:{impersonationLevel=impersonate}!\\" & _
strComputer & "\root\default:StdRegProv")

' Get list of Printers
oReg.EnumKey HKEY_LOCAL_MACHINE, strKeyPath, arrSubKeys

For Each subkey In arrSubKeys
  ' Read in HP Tray value
  strPrintPath = strKeyPath & "\" & subkey & "\PrinterDriverData"
  oReg.GetDWORDValue HKEY_LOCAL_MACHINE,strPrintPath,strValueName,dwValue
  If Not IsNull (dwValue) And dwValue = 0 Then
    'If Exists and 0 then set it to a real value to make it work
    StdOut.WriteLine subkey & ": HP Tray: " & dwValue
    oReg.SetDWORDValue HKEY_LOCAL_MACHINE,strPrintPath,strValueName,inHPValue
  End If
Next

Find Empty Moodle Courses

If you use an auto-enrolment module you will often find you have lots of courses created that are never used. We have used the LDAP and Database enrolment before and both have created large numbers of courses. Some are not used by teachers,others are just used as child courses for year wide meta courses. Either way at the end of the year you may wish to identify any class that hasn’t been used. (Perhaps to delete using the Bulk Deletion options).

No Content

Following SQL code I’ve written will generate a list containing a sum of most of the resources and activities a course has, allowing you to quickly identify those with little to no content. It bases this count on having no labels, resources, assignments, etc.

SELECT m.id, m.`shortname` , m.fullname, cCount.totalcount
FROM mdl_course m
LEFT JOIN (

SELECT courseCount.course, sum( courseCount.subcount ) AS totalcount
FROM (

SELECT course, count( * ) AS subcount
FROM mdl_resource
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_quiz
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_assignment
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_survey
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_label
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_glossary
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_homework
GROUP BY course
UNION ALL SELECT course, count( * ) AS subcount
FROM mdl_wiki
GROUP BY course
) AS courseCount
GROUP BY courseCount.course
) AS cCount ON cCount.course = m.id

You may need to edit above code if you do not have an activity installed (eg homework).

No Users

The following code generates a list of all your courses together with how many students are enrolled in each. Useful to find out if you have any courses with no one enrolled.

SELECT cr.shortname, cr.fullname, count( ra.id ) AS enrolled
FROM `mdl_course` cr
JOIN `mdl_context` ct ON ( ct.instanceid = cr.id )
LEFT JOIN `mdl_role_assignments` ra ON ( ra.contextid = ct.id )
WHERE ct.contextlevel =50
GROUP BY cr.shortname, cr.fullname
ORDER BY `enrolled` ASC

You can export either of the above queries into Excel and manipulate it from there. Order by the counts then copy the short names’ of courses to delete, paste into a text file and upload to the Bulk Course Deletion addon. Goodbye excess courses.

Data Cleanup: Roles without Users

Sometimes when a user gets deleted Moodle doesn’t clean up after it self as well as it should. The following code will list all the rows in your role assignments table that no longer match to a user:

SELECT *
FROM `mdl_role_assignments`
WHERE `userid` NOT
IN (
SELECT id
FROM mdl_user
)

If you wish to the delete all of these just run following. As always make sure you have a good backup before deleting anything from DB.

DELETE
FROM `mdl_role_assignments`
WHERE `userid` NOT
IN (
SELECT id
FROM mdl_user
)

For some useful SQL queries that can be used to identify unused courses please see Some useful Moodle SQL Queries.