Error during exporting default solution

I tried to export the whole default solution with all customizations of our testing environment. After 5 Minutes, the export stops with an error message, but no details.

Digging in the logs I found the error for a timeout:

>MSCRM Error Report:
--------------------------------------------------------------------------------------------------------
Error: Request timed out.

Error Message: Request timed out.

Error Details: Request timed out.

Source File: Not available

Line Number: Not available

Request URL: https://crm/CRM/_grid/cmds/dlg_exportsolution.aspx?appSolutionId=%7bFD140AAF-4DF4-11DD-BD17-0019B9312238%7d&command=exportsolution&ismanaged=0&optionxml=%3csettings%3e%3cexportAutoNumber%3efalse%3c%2fexportAutoNumber%3e%3cexportCalendar%3efalse%3c%2fexportCalendar%3e%3cexportCustomization%3efalse%3c%2fexportCustomization%3e%3cexportEmailTracking%3efalse%3c%2fexportEmailTracking%3e%3cexportGeneral%3efalse%3c%2fexportGeneral%3e%3cexportMarketing%3efalse%3c%2fexportMarketing%3e%3cexportOutlookSynchronization%3efalse%3c%2fexportOutlookSynchronization%3e%3cexportRelationshipRole%3efalse%3c%2fexportRelationshipRole%3e%3cexportSales%3efalse%3c%2fexportSales%3e%3cexportExternalApplications%3efalse%3c%2fexportExternalApplications%3e%3cexportIsvConfig%3efalse%3c%2fexportIsvConfig%3e%3c%2fsettings%3e

Google finds multiple entries about extending the timeout, but nether adding registry entries nor adding organization settings changed the behavior.

But the following article describes all possibilities very good: https://blogs.msdn.microsoft.com/crminthefield/2011/06/13/microsoft-dynamics-crm-timeout-settings/

Based on this article I changed the following web.config on the crm frontend server:

Original configuration:

<system.web>
    <httpRuntime executionTimeout="300" maxQueryStringLength="8192" maxRequestLength="131072" requestValidationMode="3.0" encoderType="Microsoft.Crm.CrmHttpEncoder, Microsoft.Crm" enableVersionHeader="false" />
.........
</system.web>

Changed configuration:

<system.web>
    <httpRuntime executionTimeout="900" maxQueryStringLength="8192" maxRequestLength="131072" requestValidationMode="3.0" encoderType="Microsoft.Crm.CrmHttpEncoder, Microsoft.Crm" enableVersionHeader="false" />
.........
</system.web>

Description to this step:

The parameter executionTimeout=”300″ defines, that after 300 seconds (=5 minutes) the web service stops processing the current execution. In my case, this stopped the export of the solution. I changed this value to 9000 (=15 minutes) and started the solution export again and the export finished successfully.

The exported file had a file size of about 500 MB.

Why is this solution that big?

In the default solution all customizations are included. This means also all templates and all attachments, added to the templates are also included. In my case, this caused the huge filesize.