"manage known networks" is empty in wifi settings

I rarely use wifi but noticed today after connecting that it would not reconnect automatically. I was fine with 1809 but am now on 1903, including yesterday's update. Here are the symptoms and what I have tried:

symptoms:
can connect to wifi, asks for network password, box that says "connect automatically" is checked. But then after a reboot, or just after disconnecting, it acts like it doesn't know the network and I have to sign in all over again. If I go into settings > wifi > Manage Known Networks, its just empty. Even after connecting, manage known networks is empty.

I tried uninstalling/reinstalling the wifi adapter but that did not help.

When I go into control panel > network > set up a new connection > manually connect to a wireless network, then add the ssid and password and press enter it comes back in red with "ACCESS DENIED"

Windows appears unable to save a wireless network profile. Not sure what to do next

Try the troubleshooter at Settings, Update & Security, Troubleshoot, Network Adapter, Run the troubleshooter, select Wi-Fi?

NMI said:

Try the troubleshooter at Settings, Update & Security, Troubleshoot, Network Adapter, Run the troubleshooter, select Wi-Fi?

troubleshooter finds no problems

one more item that i will add to the first post. When I go into control panel > network > set up a new connection > manually connect to a wireless network, then add the ssid and password and press enter it comes back in red with "ACCESS DENIED"

- - - Updated - - -

figured it out.

the folder C:\ProgramData\Microsoft\Wlansvc\Profiles\Interfaces, actually the Wlansvc subfolder PLUS everything below it did not even exist. No idea when that happened, and I just did a 1903 repair install this morning. Anyway, I added the Profiles folder and now all is well.

johnhoh said:

troubleshooter finds no problems

one more item that i will add to the first post. When I go into control panel > network > set up a new connection > manually connect to a wireless network, then add the ssid and password and press enter it comes back in red with "ACCESS DENIED"

This article might be of some interest to you. It might also explain why you were having issue installing the latest update with 1903:

After installing the update, also known as Windows 10 version 1903, some users are reporting losing Wi-Fi connectivity and no longer be able to connect to Bluetooth devices.

The loss of Wi-Fi connectivity is affecting Windows 10 PCs running an "outdated" Qualcomm driver for their Wi-Fi. Microsoft has said it will prevent Windows 10 1903 being automatically offered to affected PCs until an updated version of the driver is installed. In the meantime, it recommends that users "download and install an updated Wi-Fi driver from your device manufacturer", which Microsoft says should be available

Wi-Fi and Bluetooth not working after Windows 10 May 2019 Update? Here's how to fix it - TechRepublic

According to this quote, you can always try to see if there is a new driver from the manufacturer's site for your Wi-Fi.

Just in case, my solution was to set Owner to Everyone and allow full access to Everyone for the folder C:\ProgramData\Microsoft\Wlansvc\Profiles\, clean the folder content, restart the WLAN Auto-Congfig service. The known network list is full again.
As the side note, the Interface folder, which keeps the history of previously connected network, got repopulated. It looks like the folder is just a cache. The service keeps its data somewhere else.