Inconsistent Node Access on home network

Our home network of six computers (3 ethernet [win 8.1, win 7, XP], and 3 wireless [2 win 8.1, one win 7] , has begun exhibiting “you do not have permission” errors on ethernet computer 1 when attempting to open folders on ethernet computer two (no issues with ethernet computer two opening folders on ethernet computer one). This is inexplicable to me as the network configuration is quite “clean” (purposefully) with no UAC, no firewall, anti-virus disabled, permissions set at “full control” for everyone, all resources fully shared, both users having accounts on each computer, and the latest windows updates applied. Settings on the WRT1200ac router look good and are unchanged from the settings that have been in place for the last few years. I do not have an extensive knowledge of networking so maybe overlooking something obvious. Any suggestions are much appreciated.

Is it specific folders that give the problems often if someone creates a new folder they will be the owner and you wont be able to access it

No sir. Computer one can see computer two in my computer or explorer on computer one but it gives the no access error when we try to access any of the drives on computer two.

Not clear are you trying to get into a share of a hard drive that isn't shared by default he is shared as admin by hidden share starting with $ is d$

Computer one is 2600. Computer two is Force.

No new folders have been created on force by anyone but wife whose account on force has administrator privileges or me whose account on force has administrator privileges (wife and I also have administrator privileges accounts on 2600). I am unsure if the shares on force are “default shares” or “hidden shares,” but they do not read $ or E$.

When I click network in “my computer” on force, I can see the 2600 computer icon. Then, when I click on 2600 computer icon, I can see the drives in 2600. When I click on any drive in 2600, I get the “no access” error.

Here is the actual problem. A batch file on force backs up my wife's research folder (located on force) every night at midnight, was written about a year ago, and has worked flawlessly since its inception. What the batch file does: creates a directory on a USB external hard disk attached to force and names that directory the current date, then copies contents of the research folder to the current date folder on force that it just created. Then the batch file creates a directory on a USB external hard disk attached to the 2600 and names that directory the current date, then copies contents of the research folder to the current date folder on the 2600 it just created. The following morning I check the network to see if the following exist: (1) the original files in the research folder, (2) a complete copy of the research files in the current date folder on the external hard disk attached to force, and (3) a complete copy of the research files in the current date folder on the external hard disk attached to 2600. The backup procedure as described here worked perfectly until 12/19/18 when we stopped getting the backup to 2600 though we continue to get the backup to force.

Troubleshooting led me to find the force could not access the disks on the 2600 (as mentioned in my original post), and I am guessing that if force cannot access 2600 it cannot make the necessary backup to the external hard disk attached to the 2600.

In the past, we have experienced backups ceasing when the external hard disks on either computer filled so I deleted files as needed from either external hard disk to make room for the ongoing backups. Since we are now experiencing a problem with an inability to make backups to one of the external hard disks, I have now deleted all files from the external hard disk on 2600 but did not need to delete any files from the external hard disk on force as it was currently only half full.

However, we still do not get a backup on the external hard disk attached to the 2600 which I surmise is because of the no access error dialog.

Any helpful suggestions appreciated.

How does it connect to the external drive? Is the drive shared?

The external drive on force is plugged into a USB 3 drive on force. The external drive on 2600 is plugged into a USB 3 port on 2600. Before the access problem began, each computer could connect to each external drive over the network. Each external drive is shared with everyone and has full permissions enabled.

Its shared as everyone but what about ntfs permissions? Does the drive always have the same drive letter do you map the drive

Checked ntfs permissions and they are set to full control for all users. Drive letter is constant. No mapping. Power cycled modem and router to reset. Issue continues. Thank you.