stsadm -o setproperty -propertyname max-template-document-size -propertyvalue 50000000
There is a hard limit of List/Site template size of 500MB. So set the value less than 524288000 or you will get an error when saving the list as a template!
As per the above KB, You may receive error even your site template size is lesser than the conigured value! So what other options left to us? Export/Import!
In an another case, I open the site in SharePoint Designer, and deleted unused document templates from _cts folder, tried saving it again, it worked!
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