Luciano, what you are describing is not SkyDemon behaviour. Once you have downloaded a plate it will turn green, and will remain available while offline even if you terminate and restart SkyDemon. The only time it will disappear is if it's replaced by a new version, at which point you'll need to download it again.

If you are actually downloading the plate (e.g. it is turning green) then something is causing your downloaded data to be deleted. But possibly as Mike says, you're not actually downloading them at all.

Indeed, it works perfectly !
Just a matter to understand the process !
Tks

Can you reproduce it?

I had the issue again today. Here is the the list of events.
Downloaded the whole swiss VFR GUIDE a while ago.. probably more than 2 months ago.
1. I loaded a route (met-route) that I had created previously that just goes to every every airport in Switzerland that issues TAF/METAR, wifi is on at this time. I use this to have all the met data at once.
2. Went to airport, warmed up engine and while waiting created a new route from LSZG to LSGL (no wifi at this time)
3. took off, unable to load the LSGL plates (need wifi)
4. Only the plates of the airports on met-route were available.
5. no amount of restart / reboot would help.
6. The only data in the VFR GUIDE (tools - documents browser) where the plates of the met-route, nothing else at all, not white, just not there.
7. back at home, turn off wifi, still same
8. Turn on wifi, hit plates - tools - download all in list: a FEW plates are downloaded
9. The entire VFR GUIDE is back with all plates and text chapters all in green.

I can now turn off wifi and open any off the plates.
So it looks like the whole manual disappears (perhaps because it is not current anymore ?) and reappears when just hitting download all in list.

Did a few more tests, It looks like all AIPs plates I downloaded previously are gone, turning on wifi they all reappear, after turning wifi off, they are still there. But you need to access  the AIP (but not dowload it) first when wifi is on to able to acess them afterwards with wifi off.

Tried this for several AIP I had downloaded previously, same effect every time. No need to download anything, just turn on on wifi makes the stored data accessible again.
Perhaps this is all happens because some plates are outdated, but that is definitely not a nice "feature".
It is confusing, I hope this helps in finding the problem.

This is the same behavior I described earlier in this thread.

As far as we can tell, this happens when the index file becomes corrupted on your device and SkyDemon is restarted, meaning we do not have the plate index in memory any more. The plate files themselves are stored but without the index file they cannot be used. This is why once SkyDemon has a connection again, you'll see them reappear in green because they have already been downloaded. If you can give us the rough date/time you think the problem occurred we can check our error logs to see if we have a record of a failure to load the plate index (we inserted debugging code to catch this).

Not knowing your real name or account details it's a bit hard to search, but I did search for such a report from any user called Greg in the last week, and I couldn't find anything unfortunately. The actual problem event could occur any time between having downloaded all plates, and attempting to access a specific plate.

Hi Tim,

I will provide the account info to your email at skydemon.

Thanks. I searched again using the details you provided but still didn't find anything unfortunately. This points to some other reason why your index is being lost, other than the index file being corrupted. Sadly because the issue isn't repeatable with a known set of specific steps, there isn't an obvious way to go forward and help you.

Thanks Tim,

since the index can  get lost or corrupted - maybe caused by a previous Skydemon crash (happens !),
why not store a backup copy of the index so that the original file can be automatically restored in case it gets corrupted or lost.
More a workaround than a real fix but that would help in the meantime. I consider this as a P1 bug, really a loss of the most basic functionality. Additionally, you could add trace/debug code in next SD revision so that users experiencing a problem can upload traces for your analysis.

The thing is, we don't know why your device is losing the file or failing to load it. We have no reason to believe that SkyDemon would be able to load from a backup if for some reason it cannot load from the main file. Indeed, there is every reason to believe that the failure to load from one would mean failure to load from the backup. We have already spent considerable time adding debug and tracing code to the index loading routines with the result that this bug occurs significantly less often than it used to. We will continue to give it thought.