I´ve played yesterday.
Now it disappeared from installed and I could not start it?
what should I do?
starting directly from explorer the game starts but says that some dlc´s are missing.
I don´t want to download all game again.
I´ve the expansion package.
thanks

If you meant installed in Galaxy, click on + sign (top-left of the client, above installed games list), scan and import folders -> select folder and head to The Witcher 3 folder. Then verify/repair, if problem still occurs. In case you won't succeed, download DLC's pack(~500MB) and install manually.

Good luck! : )

and for the future, The Witcher 3 forum.

After you have imported your game to Galaxy and repaired it and you still have problems with missing DLCs read and do this:

Issue
If new version of the game does not want to load your save games, saying they are not compatible and GOG Galaxy says that you are up to date and the Free DLC program is installed - you may want to try the following workaround:

Workaround
1. Start the GOG Galaxy, and log in;
2. Select The Witcher 3 in the game list, and go to its configuration pane (MORE -> CONFIGURE);
3. Untick the Free DLC program checkbox (if it's checked);
4. Wait for the application to finish the uninstallation process;
5. Tick the Free DLC program checkbox;
6. Wait for the application to install the DLC;
The Free DLC program should now be installed and The Witcher 3 should be able to load your saved games.

Source: http://www.gog.com/forum/the_witcher_3_wild_hunt/workaround_to_not_working_save_games_with_patch_110/post1

I have the opposite problem. I don't own The Witcher 3, and yet I see the game's logo every time I load the "My Account" screen because of the Free DLC Program. It won't let me hide the Free DLC Program, so the game's logo just stays there, mocking me every time I click on My Account! :)

Just ask GOG support to delete the free DLC program from your account.
http://www.gog.com/support/contact

Or, don't use galaxy at all. Tried and tested browser.download of files, FTW!

just importing solve the problem. thanks