error 740 running DISM

As the error message says, if you get Error 740

PS C:\Users\matty> DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:z:\sources\sxs

Error: 740

Elevated permissions are required to run DISM.
Use an elevated command prompt to complete these tasks.

…you just have to run your Command Prompt or Powershell window ‘as Administrator’. i.e. right-click on the icon and select ‘Run as administrator’

PS C:\Windows\system32> DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:z:\sources\sxs

Deployment Image Servicing and Management tool
Version: 6.3.9600.17031

Image Version: 6.3.9600.17031

Enabling feature(s)
The operation completed successfully.
PS C:\Windows\system32>