Well last night  my W10 DAW started to download and this morning I now have version 1709. 
I have brought my W7 laptop DAW to work and as I write am updating Sonar. Tonight I will copy the CCC download folder to my main DAW and update. I'll probably have to re athorize AD etc. 
So we will see if I get the error this time. 
 
I'm hoping that this was 1703 related and that people could check in and maybe that's something that we all had in common. SO we'll see if 1709 fixes it for me, I had the same error when updating Sonar in Aug and then Sept. 
 

lenevo Thinkpad
Win 10 Home Version not sure the #
MCAfee Live Safe
 
Dll errors : CWVideoEngine.dll
                 TTSLame.dll

Thanks for posting your input is appreciated. 
Could you take the time to check the W10 version number, I think this is the one important detail
Just takes a second,,, click on the big Gear for Settings / System / look at the bottom of the list for ABOUT. 

found it cactus music ! Windows 10 version 1607.
 
SONAR Artist most current version

pwalpwal

bitflipper
That thought occurred to me, too - make all the DLLs read-only. The obvious problem with that solution is that any future updates that legitimately need to replace one of those files would fail.

yeah, not suggested as a solution but rather something that might give more info, a part of troubleshooting... it 's all very weird...

Yes, as a troubleshooting tool: if the DLLs were all read only, you might get lucky and catch the errant installer in the act because it threw up an error dialog. Unfortunately, this problem seems to be sporadic so you might have to wait a long time.
 
I'm guessing most folks who've seen it are on Windows 10, just because more of us are on W10. Cactus, didn't you say in the other thread that you got hit with it on your W10 machine but not on your W7 laptop? Could be a clue, or maybe not - there could be a great many other variables between your two computers, e.g. you probably don't have as much software installed on the laptop as on your desktop machine.
 
CWvideoengine.dll seems to come up a lot, but only recently. I don't recall it being mentioned before a week or so ago. cwvideoengine.dll (Cakewalk Video Engine) is one of the files with a recent datestamp (10-4-17), so it's likely to have been installed as part of a recent SONAR update.
 
Here's a random thought: has anyone tried to do an update while SONAR was running? I haven't ever done that (being an old-school guy I shut down everything before any install) but I'd expect the installer to raise an error when it tried to overwrite an open file. But what if it aborted mid-update and left some 0-byte files behind? Just a random thought.

Yes I think it's only windows 10 but until we hear from a few more people we won't know for sure. I update my W7 laptop first then transfer the CCC download folder to my main DAw so both are always on the same page. My W7 laptop did not throw the error. One tiny possibility is W10 is better at finding contaminated files. 
 
Well tonight all went just fine ( other than fighting with CCC being slooooow) but Sonar this time didn't throw the error at me. I opened it a few times and played some big fat songs all is good so far. 
One bummer is after I installed my Air expand pack my C drive is sitting at a dangerous 80% now. I really need to upgrade that to a 240 GB,, 120 GB  is not good. After 3 years might be time for a fresh start. 
 
Roswell- that is real interesting and valuable info that your actually on a Pre Creators W10. That points back at what Chuck has been thinking it might be folks running Mcafee AV as far as the  CWVideoEngine.dll and the   TTSLame.dll 
go. Until other check in we cannot speculate. 

if it were an av app doing this, maybe there's something in that app's log/history?
also, have we looked in windows event log yet? a file write failure might be in the system log, or the security log if it fails due to a permissions issue
alsoalso, i haven't seen this issue reported in the steam forums

even more interesting.. MC7 users are experiencing this now. Just saw this post this AM
 
http://forum.cakewalk.com/I-have-to-reinstall-MC7-everytime-to-open-it-m3675913.aspx
 
another interesting tid-bit I think is that after I roll back and do a reinstall it will load for three or four times then the error will come up later.

MC is working fine on my desktop and it is windows 10 v 1703. Interestingly enough it didn’t receive the mcAfee update over last weekend. The desktop is an HP all in one.

McAfee AV certainly seems to be a common factor for users on the Unity forum. The following information comes directly from McAfee...
 
Files become 0 kilobyte and locked when VirusScan Enterprise / Double-Take software
As of VSE 8.8  Patch 1 and VSE 8.7i Patch 5, the VSE kernel level drivers have adopted the Microsoft Filter Manager minifilter driver model to improve supportability and compatibility with Windows and Windows applications. Double-Take software uses drivers to monitor for changes to all protected files to see what bytes have changed. When VSE is present with these Double-Take drivers it can lead to the 0 kb locked files.
 
Possibly coincidental, but disabling McAfee and reinstalling Cakewalk could be worth a try.