When I log into my system I have a KDE Wallet password dialog. When I disable it, some passwords as wifi or FTP accounts don't work any more, and the main problem - I dont have "remember password" any more.
For example I disable KDE Wallet, reboot, and I have no KDE Wallet dialog, but my WiFi can't connect, it doesn't ask for password, just "connecting", I give it 10 minutes, then delete (remove) the connection, after recreating it everything is fine.
Please help. Kubuntu 12.04
I solved this issue by going into the network manager settings by clicking the wifi/network icon in the taskbar > Settings icon, and then from the networks screen that appears, I right-clicked my connection, clicked edit, and then under the "General configuration" tab, ticked the "All users may connect to this network" check box. When I restarted my computer, I wasn't asked to enter the kwallet password and connected to my network automatically.
Perhaps this solution may also solve the problem you are having with kwallet.
KDE Wallet is the component that does the actual remembering of passwords in a KDE environment.
You could set an empty password, but here’s a suggestion for something to set first: Open KWalletManager and use Settings → Configure Wallet… then untick the checkbox “Close when last application stops using it”. That way, you only need to open it once at system start, then it keeps running and provides you with passwords, while still storing them on disc only in an encrypted form (which it cannot do without a wallet password, obviously).
Verax gave the best solution in comment:
In addition to setting the "All users may connect to this network" as user311982 described (Which I find is only disabled by default for Wifi networks, not Ethernet), which by itself didn't do the trick for me I found the KDE Connection Settings Module, after selecting a Wi-Fi network and navigating to the "Wi-Fi Security" tab: 
It makes sense that you'd need to choose "Store password for all users" instead of the default "Store password for this user only" so that the password may be accessed before you unlock the wallet.
I have Kubuntu 20.04.1 installed and I was facing the same issue; neither the WiFi password nor my Chrome passwords were being saved.
I had enabled the automatic login during the installation, and what worked for me was disabling automatic login in System Settings > Account Details > User Manager.
None of this worked for me but here is how I disabled it (Kwallet) in Plasma 5.
This solved the Wifi issue and Chrome's annoyance - both always requesting a password .... read on - it's kinda simple,
Kwallet Annoyance (Wifi and Chrome) • You can edit file ~/.kde/share/config/kwalletrc - adding to [Wallet] section just one line
Enabled=false
save quit reboot problem gone - I hope it helps
Mark
If In doubt, use arch wiki! (https://wiki.archlinux.org/index.php/KDE_Wallet)
1) Install kwallet-pam
2) Edit your display manager to execute pam_kwallet5.so and pam_kwallet5.so auto_start, as a optional auth and a optional session respectively.
3) Profit $$$
