@TheCarsForever 

From what you describe, it appears your wireless devices connect to Deco Guest network. To access shared folders from Windows 10 computer on wired network, they should be connected to Deco Main network.

When you run Deco in Router mode, it can provide Main and, optionally, Guest WiFi networks. You have both enabled. Deco Guest network is isolated from Main network, devices connected to Guest network can't access anything on Main Network.

All wired devices belong to Main Network.

This specifically: "Windows 10 computer on wired network has shared folders that are not accessible to devices on wireless, but work fine for systems on wired network. Connecting wireless device, such as a laptop, to the wired network restores share access." 

It can be explained if your devices on wireless, including laptop, are connected to Guest network. Windows 10 computer is wired and on Main network. When you connect laptop to the wired network, it also becomes part of Deco Main network.

@Alexandre. Thanks for the quick response. I apologize I was unclear in my original message.  I am confident that the wireless devices are connecting to the primary Network and not the guest network. I have named them in a way that is easy to identify, and do purposely use the guest Network for certain devices and for visitors. The really odd thing, that I also neglected to mention in my original post, is that access to the shares did work for a very brief time after I set up the Deco Network. Other than updating The Deco firmware, I had made no changes to the network or the devices between the time it did briefly work and when it stopped. Again, if I switch back to the original wireless network, excluding The Deco wireless, all sharing works without a problem.  Prior to my last post, I confirmed that all of the portable devices not able to access the windows share as well as the Chromecast fob are using the main wireless Network.  I really wish it was this simple, as it is quite problematic not having access to the shares and being unable to use the Chromecast fob.  Any other thoughts?

@TheCarsForever 

You know what they say: "The simplest explanation is always the most likely." I am not ready to dismiss "not connected to Main network" explanation.

What you can do is turn off Guest network, for the purpose of troubleshooting, and see if laptop can still connect wirelessly, you can see it in Deco app, and if laptop still can't access shared folders.

After that test, you can turn Guest network back on. 

Also, but this is dependent on your technical knowledge, start with basic network troubleshooting. When laptop connected by Ethernet, can you ping from it Windows 10 computer? If answer is "yes" - can you do the same when laptop is connected wirelessly? Because, if wirelessly ping fails and when wired - ping successful, that has nothing to do with Windows shares. It is basic networking connectivity.

Bugs in router software happen, but if two computers on same Deco Main network can't ping each other, that would be major issue at TP-Link Support and in this forum, yet all is quiet.

Then, I would run ipconfig on wirelessly connected laptop to see if it gets IP address and default gateway from Deco. Just to eliminate possibility of laptop not connecting to Deco mesh at all, but accessing some other WiFi network (don't be skeptical, things happen).

Laptop wirelessly connected should be getting IP address in the same range as Windows 10 computer, and also their default gateway should be the same (which is Main Deco).

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Also, it would help TP-Link support if you would do all these tests and can simplify problem description to "Laptop wired to Deco mesh can ping Windows 10 computer wired to Deco mesh, but laptop connected wirelessly to Deco Main network can't ping that same Windows 10 computer wired to Deco mesh." 

Issues like these are much easier to troubleshoot than shared folders. You can even start separate thread with that new problem description, if you confirmed it is true, and I am guessing it will catch attention of TP-Link Support.

@Alexandre. Thanks again for your quick attempts to help out.  For clarity, I have been a network engineer in my career, though not in my current position.  Over time I have performed analysis/testing such as you noted regularly and have done most of what you noted prior to posting.  That said, I was hoping this was a 'check this setting' type of situation.  This is a family member's network and my real hope was to put in a mesh network they could manage once it is up and running.  While I can dig in much deeper, there is only so far I want to go with this and am hopeful I don't need to start sniffing packets. 

Before I send the details noted in the last message, let me confirm something that could be playing a role.  The wired network, via the ISP provided modem/router, is using the 192.168.0.x IP range and the Deco is using 192.168.68.50 to 192.168.71.250 for DHCP.  While this setup makes sense, I did attempt to change it so both networks were on the same subnet but get an error noting that the LAN and WAN cannot be on the same subnet which was not a real surprise.  Again, the reason for using a consumer grade mesh network for these folks was based on the assumption that the traffic will travel between wired and wireless without needing me to get overly involved in setup and configuration.  I did want to note seeing this though in case there is something that indeed does need to be changed.

If this doesn't provide a smoking gun I will detail the troubleshooting noted in the last post.

Thanks again for your help!

@Alexandre. I am very sorry about not being clear regarding this originally!  As I noted in my last post, I assumed - obviously falsely - that the Deco was handling routing between the two networks.  Makes sense why it is not now and I will talk with the family member to decide the route to go but suspect they will opt for Access Point mode since there is little functional difference for them and it doesn't require any new equipment.  Thanks again for your patience and help!

@Alexandre. I wanted to pass along my thanks again for your help with this.  My assumption that the Deco would act as a gateway between the two networks by default was in error and sorry again for not clarifying that I made this assumption.  Changing to from the default router mode to access point resolved the issues using Windows shares.  The Chromecast fob also started working after this change which seemed a little more odd since it was always on the same wireless network as the phone attempting to communicate with it.  For the family members using this setup losing out on some of the Deco specific additional features is not an issue, but will look at using a switch if they end up being needed later on.  Thanks again for your time and patience getting this solved!