Merge-SPLogFile- Doesn't return me any records - powershell

Question

thanks for taking the time to try any help me out!
As the title suggests I cannot get the Merge-SPLogFile cmdlet to return me any results!
I find hunting down error messages in SharePoint logs a very time consuming and laborious process- Being relatively new to PowerShell I only recently stumbled across the cmdlet. Knowing how much time this could save me I was excited to implement it.
I started with the following code:
Add-PSSnapin Microsoft.SharePoint.Powershell
$correlationId = "C826869C-4A8E-10E2-6C5E-58A1C87EB651"
Merge-SPLogFile –Path “C:\Users\Administrator\Desktop\SPLog.log” –Correlation $correlationId -Overwrite
This gives me the warning- "WARNING: Cmdlet did not return any records in the log file. Check your time range or filters."
Naturally I typed the error into my search engine and it seems other people have had the same problems when the -Correlation argument isn't in upper case. I tried both uppercase and lowercase but to no avail. I was able to manually find the GUID in the logs so I know it exists.
When I ran out of luck with this technique I thought I would try filtering using different arguments (by time):
Add-PSSnapin Microsoft.SharePoint.Powershell
[int] $HowFarBack = 15
[int] $howFarBackInMinutes = (-1) * $HowFarBack
[datetime] $startDateTime = [System.DateTime]::Now.AddMinutes($howFarBackInMinutes)
write-host $startDateTime
Merge-SPLogFile -Path 'C:\Users\Administrator\Desktop\SPLog.log' -Overwrite -StartTime $startDateTime
I get exactly the same error. To rule out my arguments being incorrect I tried not giving it a filter at all:
Add-PSSnapin Microsoft.SharePoint.Powershell
Merge-SPLogFile -Path 'C:\Users\Administrator\Desktop\SPLog.log' -Overwrite
I still get- "WARNING: Cmdlet did not return any records in the log file. Check your time range or filters." The logs are all there and in the default "LOG" folder within the 15 hive. I haven't changed any logging settings away from the defaults.
I am running on SharePoint 2013 Foundation.
What am I doing wrong?

Answer 1

The problem in my case was that there was no diagnostic logging activated for my SharePoint Farm.
How to enable diagnostic logging
Go to your Central Administration (usually http://YOUR_SHAREPOINT:10000/) (there is also a shortcut in your start menu on the server you installed the SharePoint at)
Go to "Monitoring"
Under "Reporting" click "Configure diagnostic logging"
Select the categories that you want to merge in case of an Error. I just selected All Categories here. Then click the "Ok" button at the bottom of the page.
(5. Reproduce the error and use the SP Shell again to Merge the Log Files)