Hi, I created a thread with a similar problem here
shares on Win 7 PC - Windows 10 Forums
I have now resolved this issue which "may" help other users who are having issues accessing shares on Vista/7/8/10.
By the way I should say I don't use the HomeGroup feature so it's not a factor and apologies for this being a bit TL;DR bait.
I have never had network/share issues on systems running any flavour of Windows 7 before now and it was only trying to get my Win 10 box to see a share on a Windows 7 box that I ran into problems. However I now realise this was more by luck than design
Firstly the SMB fix described by DaveI was required (on the Win 10 box) as I got the access denied issue trying to open a network location (at least on the first attempt) usually I could open a network location on subsequent attempts and see (but not access) the shares. After disabling SMB 2/3 I could access network locations without errors but not access the shares due to not having the required permissions. I had never encountered this problem before. Oddly I "could" access the share on my Win 10 box from the Win 7 box but not the other way around.
Normally to enable sharing, I click the Properties link on the item I want to share, go to the Sharing tab and Click the "Advanced Sharing" button (for me the SHARE button is always grayed out - I assume this is normal?)
I then click the "Enable Share this Folder" box, then click the "Permissions" button.
The Group or Username in this dialogue is always "Everyone" and I select the required permission check boxes and click OK.
This has always worked up to now.
However, I always set my PC's up with the SAME user/password as administrator as default and I also disable "Allow password protected sharing" and it's always worked I can access the shares from any pc to any other without entering a username/password and without any permissions issues - until I tried accessing my Win 7 box from my Win 10 box.
Ok, so I couldn't access a share on my Win 7 box from Win 10 as I kept getting the "You do not have permission" issue. So I checked the sharing between this Win 7 box and another Win 7 box I had previously been able to access without issue and I was getting a Username/Password dialogue which I hadn't seen before. I was begining to think it was an update to 7 or something that was causing the issue.
However I now know that accessing a share on computer (B) from computer (A) where the username is the same on both PC's will trigger a login dialogue (regardless or whether password protected sharing is enabled or not) if the password on either PC is different (different can also mean no password for one of the user instances as well).
So I removed the password from the one account so both instances were password free and tried to access a share but I then got a "You do not have permission" message.
I couldn't understand this as I'd given full control to "Everyone" and Everyone is everyone right? apparently not "Everyone" is a specific user group - i.e not authenticated, system,administrator or user (on the system where the share resides, I assume).
I went into the Properties/Security tab of the share I was trying to access and sure enough the user group "Everyone" wasn't included in the "Group or Usernames" box although Authenticated users,SYSTEM,Administrators and Users were listed.
So I had to click the "Edit" button then "Add" button and type "Everyone" (as that's the default user group when I originally enabled sharing) into the object box then click "OK"
This usergroup now appears in the list on the Security tab and the list of permissions can be changed here as required.
This explains why sharing worked originally as all PC's had the same user name/password and "Authenticated Users" was already in the Group/Username box of the Security tab.
This explains why I couldn't access the share between the two Win 7 boxes as I had removed the password on one of them (but I hadn't tried to access a share since so I didn't realise it was broken).
It also explains why I could access the Win 10 share from the Win 7 box as the Win 10 share was on an SD card and the default User Group in the security tab for this drive was already (and only) "Everyone"
Networking, it's a bit of a bother....