Once awhile back a few builds I was getting error also. I deleted everything in folder and folder and started over with instructions. Not knowing what I did different but did have a good outcome? Good luck to you my friend
You may have a bad ESD file.
If you can, get Windows Update to download again, (all the files all over again), and grab the ESD file, copying it to the desktop as soon as the "download is at 100%" but before it starts to install.
I know that one time, I copied my ESD file as soon as it showed in the folder, then copied it again as soon as the first one was finished copying, and I found that there was a 1byte difference between the two files. One worked with the ESD to ISO tool, and the other failed.
ESD to ISO - YouTube
This is a temporary video created by our member Kari. It will help you to see how to grab the ESD file at the right time. Watch how he keeps refreshing the file folder, as he waits for the ESD file to appear.
Could it because of not enough free space on the disk ? I made those conversions usually next day or later, well after it was installed.
I do not know reason why but Windows update is not showing Build 10525 any more. Therfore, I can not down load it again. Realy I do not know why disappered from my Windows update.
Also, Dynamic Update for Windows 10 Insider Preview for x64-based Systems (KB3062501) is failed to install and never show it up in Windows update to re-install it.
I am confusing now realy what is problem.
I myself switched to slow ring, and it has not come through for me yet. I will be patient. I know I will eventually get everything, so as long as Windows Defender keeps updating, I am okay.
p.s. changing from one "ring" to the other could have a delay of 24 hours before you see anything.
YES, Build 10525 has not much features but just interested for the memory management.
I will wait for a next major upgrade if MS has it. Still Ccortana is not yet ready to use for Japanese version of the Windows 10.
Thank you so much for all of your help and attention. BR