Hello! 

I'm the license and install specialist here at Zemax. So far I have not seen a similar problem with older releases in Windows 10. How did you find it was NET related? Do you have any error messages from OpticStudio or windows event logs you can attach to this thread? Also, there may be an error logged in Documents\zemax\license folder. Attach any Key_StatXXX.log files from that folder to a reply. 

Thanks and best regards,

Don D

Hi Don,

Thanks so much for your reply and help.

I've thought of Net Framework due to 2 reasons:

1. The latest Windows 10 update (and the only update between the time it was working and time it stopped) was KB4598242 for 3.5 and 4.8 .NET Framework

2. Through Win 10 EventViewer I was able to identify the problematic modules: mscorlib.ni.dll and clr.dll

Here let me attach screenshot for mscorlib.ni.dll (sorry for the log being in Russian, not sure how to automatically translate this to English)

After that I was able to find clr.dll and mscorlib.dll in Microsoft.Net corresponding folder.

But now, after you pointing out this might be a license issue, I've looked at key_stat files - and indeed, it seems odd.

I've got 2 key_stat files from today (attaching them) and seems there's some indication that there was an error.

Strange, because when launching, OS 16.5 didn't mention about any key problems.

Thanks so-so much for your help!

Best regards,

Vadim

Thanks!

No, this isn't a license issue as I see it's finding the license just fine. Opticstudio just stores some logs in that license folder. The key_Stat logs are pretty generic unfortunately but it does indicate .NET a well.

I checked and have that same Windows 10 update installed. 16.5 works just fine for me ao it's not an outright compatibility issue at least. 

Perhaps the update didn't install correctly? You could remove it and reinstall it - A direct download is available hee:  

 https://www.catalog.update.microsoft.com/Search.aspx?q=KB4598242

It also wouldnt hurt to repair the Visual C 2015 or 2017 redistributables (whichever you have). 

https://my.zemax.com/Knowledge-Base/kb-article/?ka=KA-01512#nothingvc

Hi Don,

Thanks so much for your advices and help.

First of all, I'm sorry, I wrote wrong number of Win 10 Update - KB4598299 is a correct one.

Nevetheless, I followed your advice and basicaly deleted and then manually installed all the recent updates.

As well did it with all the needed Visual C files.

Unfortunately - no progress, still the same.

Since I've already also tried even restoring the system to a day before the updates and even this didn't help, I'm thinking about reastoring to initial condition.

No matter how much I don't want this, I guess this is the fastest way to get it back up again :)

Thanks so much!

Best regards,

Vadim 

Also, let me add if it helps - same thing happened couple of months ago on another PC.

At that time I had there 2 licenses and 2 OpticStudio versions: 16.5 and 20.3 (as I recall)

While 16.5 stopped working like now, 20.3 continued working with no problem at all.

Not sure, if this can lead to some idea - but just in case.

Thanks in advance,

Best regards,

Vadim

Hi everyone,

Ok, seems the problem is confirmed by Microsoft:

https://www.windowslatest.com/2021/02/06/microsoft-confirms-windows-10-update-bug-is-crashing-some-apps/

Thanks in advance,

Best regards,

Vadim

Thanks! 

I tried installing this update and 16.5 continues to work fine for me - Which 16.5 service pack release do you have? You can open the Zemax LIcense Manager and tell me the date at the top of it to get it. 

Take care

Don D

Hi Don,

Thanks so much for your help!

Awesome, that it doesn't impact your side - frankly, I truly hope I'm the only one.

I tried to do it on 15.5, 16.5 SP1 and SP3 - all of them experienced the same issue (21.1 is working just fine).

Tried also reinstalling them.

Here's the one that I'm using now: 'December 14, 2016' (date at the top of License Manager)

Thanks in advance,

Best regards,

Vadim

Ok thanks! We so far havent had other reports like this. However, most people with 16.5 aren't eliguble to contact us for support any longer anyway, so we may not have a way to know for sure. I tried that release too and no problems. I wish i had some other trick to share, but can't think of anything else at this time, sorry. You may have to wait to see if Microsoft puts out a replacement update. 

Best regards,

Don D

There are new updates to Windows and .NET out today, BTW. Feb 9

Wow, odd issue. Thanks for sharing the fix! Sometimes we do have people rename the Zemax folder entirely to force a recopy of all samples and rule out corrupt files. I don't understand why macros might cause this but glad you found the cause!