While doing routine WordPress updates I came across this error:
cURL error 18: transfer closed with X bytes remaining to read
After some investigation I found that my hosting server was unable to download files. Much of the advice I found suggests issues with cURL, PHP, or WordPress. If possible I advise checking the host server first. Verify that it can download the update file.
Attempting to get PHP 5.6 running on Windows Server 2012 (IIS 8) I started receiving generic 500 errors.
I enabled Failed Request tracing and reviewed the trace.
The trace revealed this error:
ModuleName FastCgiModule ErrorCode The extended attributes are inconsistent. (0xff)
The problem was a missing Visual C++ runtime.
Ensure the appropriate VC++ runtime is installed for the version of PHP running.
In this case I needed the VC++ 11 runtime.
An information technology professional with twenty one year's experience in systems administration, computer programming, requirements gathering, customer service, and technical support.