Activate button is disabled for my new solution

Question

I am facing a problem in activating a solution (.WSP) which represents a site template inside my solution gallery. here is the full senario:-

1. i create a site collection , and for this site collection i create a new master page /Sites/CS.
2. now under this site collection i create a new subsite /sites/cs/subsiteA . but this new sub-site did not get the custom master page.
3. so i went back to my site collection>>site settings>>master page>> and i chose to reset the master page for all the sub-sites.
4. so now subsiteA got the new master page.
5. i save subsiteA as template. and i create a new sub-site based on the template.

Now the problem is that the new sub-site will not get the custom master page also. now i search for this problem and i find this link which talks about similar problem :-

jeffreypaarhuis.com/2011/10/21/your-master-page-automatically-on-newly-created-subsites/

so i did the following steps:-

1.I download the site template (.wsp) from "Site Settings" >> "Solution Gallery".

2.using visual studio i import the wsp inside Visual Studio as per this link https://msdn.microsoft.com/en-us/library/ee231603.aspx#Anchor_3

3.then inside visual studio i modify the master page url inside the XML file from :-

> <Configuration ID="0" Name="Default"
> MasterUrl="_catalogs/masterpage/seatle.master" CustomMasterUrl=""
> ThemedCssFolderUrl="">

to

> <Configuration ID="0" Name="Default"
> MasterUrl="_catalogs/masterpage/Custom.master" CustomMasterUrl=""
> ThemedCssFolderUrl="">

4.then i build & publish the project inside visual studio, which created an updated WSP file representing the site template with the new master page URL.

5.then i went back to solution gallery, and i upload the updated WSP file inside the solution gallery.

6.but now the problem is that the "Activate" button is disabled, as follow:-

so i am unable to activate the template and use it in creating new sub-sites.. so now sure where is the problem ?

Answer 1

Inside Visual Studio, try to switch off assembly inclusion:

Then republish and re-upload template once again.