If anyone is still having problems with HDR Efex Pro2 and/or Color Efex Pro4 when accessing them from within Lightroom 5 (following Google's "automatic update" to install Analog Efex), then Google have just put out this solution, which seems much simpler than anyone had imagined!!
In those programs, click on the "Settings" tab in the lower left corner of the screen. Then click on the "GPU" tab. Then uncheck the box "Enable GPU Processing", click OK, and close the program.
Next time you try to use it, it will work like it used to. You'll need to do the above separately for HDR Efex Pro2 and Color Efex Pro4 if both programs were affected.
It is nice when things turn out to be much simpler than the geeks imagined.
