If there's a free weekend, you sync your account, and then can't enter a giveaway...

This is a recurring issue caused by differences between Steam and SteamGifts. I thought I would post this here as a response to any future "I can't enter giveaways for a game I don't own" threads.

The technical explanation:

• The Steam API does not always update at convenient times.
• Free Weekends involve an API update, but there isn't one after the Weekend expires.
• Playing a game during its free weekend means you will "own" the game for up to two weeks after the weekend expires.
• SteamGifts syncing works with the Steam API.
• Syncing your SG account during a Free Weekend will prevent you from entering all giveaways for that game.
• Until the Steam API is "recalibrated" properly, syncing your SG account won't reset your free-weekend-game status..
• Adding a game or DLC (or joining a Steam group?) apparently forces a refresh of the Steam API.

What this means to you:

• Sync your SG account before any free weekend. (Wednesday or Thursday is good.)
• If you get locked out of giveaways for a game you do not own, wait until "temporary ownership" expires and re-sync.
• An alternative is to redeem a game or DLC to your account. This should refresh Steam's API. Then, sync your SG account.

Note: It has been rumored that joining a Steam group may also refresh the API, but this has not been confirmed.

If there are any additions or corrections that need to be made (or adjustments for clarity's sake), please let me know and I will edit this. Special thanks go out to all of those who have worked on finding this solution and letting those of us at SG know about it.