Pdh.dll errors are caused by situations that lead to the deletion or corruption of the Windows Performance Data Helper (PDH) DLL file. In some cases, pdh.dll errors can indicate a registry problem, a virus or malware issue, or even a hardware failure.

Follow these steps in the order they are listed below to try the simpler solutions first.

Recover pdh.dll from Recycle Bin. The simplest possible cause of a "missing" pdh.dll file is that you accidentally deleted it.

If you suspect this, but you've already emptied the Recycle Bin, you may be able to recover the file with a free file recovery program.