iMac Internet Sharing Wi-Fi network not visible, channel blank

Hi,

You must turn on your Mac's Wi-Fi and connect to a network before opening Sharing settings to populate the channel list.

Toggle and restart: Turn Internet Sharing off, restart your iMac, and turn it back on.

If the channel still remains blank, corrupted preference files are likely blocking the configuration.

1. Open Finder and press Shift + Command + G.
2. Paste /Library/Preferences/SystemConfiguration/ and press Enter.
3. Locate and back up these files to a safe folder on your desktop:

• • com.apple.nat.plist
  • NetworkInterfaces.plist
  • preferences.plist

1. Delete the original files from the SystemConfiguration folder.
2. Restart your iMac so macOS can generate fresh, uncorrupted configuration files.
3. Reconfigure your Internet Sharing settings.

If still channel is blank, contact Apple Support and ask about it. It could be possible that it might be bug of macOS.

1) update your iMac to 26.6.2

What's new in the updates for macOS Tahoe 26 - Apple Support

2) revisit the Internet Sharing support article.

Share the internet connection on Mac with other network users - Apple Support

Using a Wi-Fi travel router or a Wi-Fi router will be easier than using a Mac as an expensive and sometimes problematic network router, if that added Wi-Fi hardware is at all an option here.

kcoyle wrote:

router died

If it is an ISP-provided router, let the ISP know.

Otherwise, there are replacement options available at a range of prices and features.