What does the gray Waiting app icon mean?

After restoring a backup to your iPhone, you likely will see some grayed icons in place of your apps, and some may say "Waiting" underneath the icons. (This is applicable for restoring iTunes and iCloud backups to iPhone, iPad, and iPod Touch.)

An iOS backup doesn't store the apps themselves; the backup contains the app's data as well as some "notes" about what apps need to be re-downloaded from the app store. The grayed waiting icons are placeholders for those apps so you can see the progress of the apps still downloading from the App Store. Don't delete the gray "Waiting" icon, or it will delete the app data along with it (just as if you deleted the app.)

After your restore, the app downloads from the App Store are supposed to initiate immediately, but since iOS 10.3, we've seen an uptick in the downloads getting stuck.

If you have a bunch of gray app icons after restoring a backup to your iPhone, here are a couple of things to try:

1. Plug your iPhone back into a power source. Hang out a second because you may get a prompt or two about allowing location data to Apple Wallet and such. You should see a little waiting indicator next to the battery indicator at the top of your screen while the app download starts up, and then you should see the first app start installing.
2. Make sure there's free space available on the iPhone. This should only be a concern if you're restoring to a smaller device than the one that made the original backup, but still good to verify. If there's no free space on the iPhone, the app downloads will all stay in "Waiting..." status. You can check the available free space in the Settings app > General > Storage & iCloud Usage > Available under "STORAGE".
3. Turn off the iPhone and turn it back on. I've used the reboot to give iOS a little "kick" and get the downloads started again. (Especially after having to clear out space from #2.)
4. If you open the App Store app, and go into Updates, do you see the apps available with a cloud download icon on the right? You can try tapping the cloud for one to get it installed and it should replace the gray icon. (You shouldn't have to tap the cloud icon for all of them, but it's certainly an option.)
5. (Addition May 18, 2017) As I mentioned above, since the iOS 10.3 release, we've seen an increase in these downloads getting stuck. We've seen at least once case where waiting about 15-20 minutes solved the problem, and the apps started downloading again. So if you're feeling patient, we recommend trying waiting about a half an hour (on wifi, plugged in!) and see if any apps start downloading. (If this works for you, please leave a comment so we know the suggestion is helping!)

If you find another method to unstick your stuck Waiting grayed App Icons after a restore, definitely leave a comment below with what worked for you!