Steam error: Could not connect to a network on Windows 10

It looks like similar users share your frustration for this annoyingly horrible issue:

However, it seems there are several fixes for this that have worked for other users:

Solution A:

Rolo: for me, this problem was caused by a optional windows update, ralink wlan 802.11n usb wireless lan card. I fixed it by going to device manager, network adapters, driver, roll back drivers. hope this helps someone.

Solution B (similar to A, for Win7):

Seismoid: I had the same problem with my steam client ("Could not connect to steam network", then after deleting everything but steam.exe and /steamapps folder "steam client has to be online to update", then after uninstalling steam and trying to reinstall it took ~20 tries until it downloaded the 110mb without error, but still kept getting errors that it could not connect to steam network). In my case I just took a look at the windows update history (win7) and found out that the wlan driver was updated on march 5th. So I rolled back that update and everything worked again. You might want to give it a try if you have similar issues with your steam client as those mentioned in this thread.

(I use Windows 7) First you should check if there is an update of your wireless driver in the update history.

1. Go to Control Panel -> System and Security -> Windows Update
2. On the left side click "View update history"
3. Look for a line that says "Ralink - WLAN - ..." (in my case it was "Ralink - WLAN - D-Link DWA-140 RAngeBooster N USB Adapter", my wlan stick); hint: you just have to check the last 2-3 weeks - or whenever your steam client stopped working - so sort the updates by a click on "Date Installed" at the top ;)
4. If there was an update and you want to try to roll back:
5. go to Control Panel -> System and Security -> System
6. click on "Device Manager" on the left side
7. expand the "Network adapters" node in the device tree
8. right-click on your wireless adapter mentioned earlier (here it only says "D-Link DWA-140 ..." - no "Ralink - WLAN -" as prefix)
9. choose "Properties" in the context menu
10. go to the "Driver" tab and click "Roll Back Driver"
11. wait until windows is done rolling back (you may need to restart; though I didn't have to)
12. dont install those drivers again if steam client works now :) (might need to deactivate automatic windows updates)

It seems in most of the cases, Steam's problem stems from a bad Wi-fi or network driver. It also doesn't hurt to check your antivirus or any firewalls running. See if disabling all anti-virus software while running Steam should work. Some users have found that their AVs were in fact blocking Steam.

Some of the obvious solutions are:

• Trying (not changing permanently) compability mode: Windows 8
• Updating your AMD or nVidia driver to the latest (or sometimes even Beta).
• And as always, try disabling all firewalls, anti-virus software and NEVER install "Improve your computer", "Clean your PC", "boost your PC" or "Malware remover" applications, these are 99% of the time viruses in themselves.
• (as Frank V. pointed out) If multiple applications (not just steam) acts up on you, crashing, hanging, being extremely slow and you've updated from Windows 7 -> 8 -> 8.1 or even just from Windows 8 to Windows 8.1.. Consider reinstalling the PC with a Clean fresh install of 8.1 right off the bat, it might solve a lot of funky problems.

Now to the more Steam specifics, I tried to search numerous posts and all of the community posts were inconclusive.
A few things that really worked was:

• Deleting ..\Steam\appcache - Clears most information that steam knows about your profile, games etc. This might loosen up the pipes. (Don't worry, it won't delete the games themselves)
• Checking ..\Steam\steam.log might give you a clue of what went wrong.
• Launching steam with the parameter -console might give some clue of why the game is lagging if it starts.
• If steam now starts, but the game is still lagging after these steps, try "verify local game cache"
• If for whatever reason the game still lags but steam itself is working, try right-clicking the game in your library and select "Clear local files" (essentially uninstalling the game) and install the game again.

Again, wrote this because google didn't find any compiled tips about why steam fails on Windows 8.1.