Hello Dave
A very bleary-eyed good morrow. Been playing around with this 'til t' early hours. Assorted thoughts in no particular order some of which could've been a product of carrying out the scan/update process multiple times and then some.
When running M/rwys it occasionally produced the Runways.txt file vers 3.98 and not 4.34. This produced an error in the u/d process.
Two or three times when I disabled sceneries M/rwys failed to produce f5 and t5 files again producing error in u/d.
Once M/rwys failed to produce the Runways.XML file.
It eventually became clear that after running M/rwys it is a good idea to check that the file production is correct before attempting the PFE u/d process

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What I did discover is that M/rwys certainly does not like Scotflight's V.2 Scotland scenery. This caused a substantial stall in the scan process when enabled. Even when disabled, an attempt was made to scan the coast files of this particular scenery.
There was also a problem with Aerosoft's London City airport scenery. With this enabled the scan and u/d process worked fine but when I came to test a flight from this airport in FS, PFE closed down and I got the error messages I mentioned previously.
Finally I removed both of these add ons. The scan and u/d process worked and I was able to use PFE on a test flight from the default City airport. Whilst this is mildly pleasing, it does seem to mean that I cannot use PFE with the City add on and as this is my home airport it kind of defeats the object.
This little exercise also prompted a memory that one of the issues I emailed to you a while ago was at an airport in Austria. This happened after I installed Austria Pro scenery and leads me to wonder if this problem has its roots in the u/d process too.
Is there any way to manually alter the M/rwys files to avaoid these issues?
Sorry I seem to be blabbering now - I'll go back to bed

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Bernie