Problem with downloading from CMS Media Library

[belax]

Dear Sir,

My configuration is:
Xibo CMS 1.8.7
Windows Server 2012 R2, IIS server.

Problem:
I can not download files with size bigger ~ 80 Mbs.
What happens: In the Library I choose a media (100 Mb video in size), in the drop-down menu I choose “download”. After that Browser waits for about 12 seconds for response and then a new tab appears with
address in the address bar: “http://myserveraddress.com/library/download/86?attachment=All010760fps.webm”.
And its contet as below:

This page isn’t working
myserveraddress.com is currently unable to handle this request.
HTTP ERROR 500

Also, what I have noticed: The time it waits proportional to the size of a media file. For e.g. if I want to Download 70 Mb files - it waits for about 8 seconds and then download dialog box appears.

What settings in IIS or php.ini should I change?
Thank you.

[Peter]

Please check the php and iis settings here How do I upload files bigger than 2MB / How can I increase the upload file size limit?

Could you also tell us what is the library path specified in the CMS settings?

It could be also a good idea to upgrade the CMS to 1.8.9 version.

[belax]

Ok. I will check.
For me it looks like something with execution time.
It is actually very strange - why does it take so much time (seconds) to start download files.
Could you please check on your machine if “download-prepare” time depends on the size of the file.
My Library path in CMS is (without quotes) :"C:\WebSite\xibo187p_lib"

Here are main php.ini settings.