You need to be able to run that mentioned occ command as your webservers user to solve this.
Thats the only chance to update oC's filecache which got very likely broken by the mentioned and unsupported modifications within the datadir.
hi RealRancor,
i cant run any sudo commands. Its shared hosting. There must be another way. Is there no command I can run directly in the database with phpmyadmin?
Which unsuported modifications do you talk about? I am a bit lost here...
I still need help with this but support is very thin here.
As i mentioned i cant run any sudo commands because i am on shared hosting. Nobody can or want help? to bad.
RealRancor send you already a link that manually putting files is not supported. With webhosting, this is difficult to handle.
What you can try: Open the existing folder (as close as you can get in the file structure), then create a new textfiles, make little changes. This sometimes triggers to update the file-index of this specific folder. If that doesn't work, there is no other way than upload the files via webinterface, oc-client or webdav.
Hello guys. i wanna clarify some things.
its not about manually putting files. its about files and folders i have no longer access too but had bevore. this were not manually uploaded.
I had access to all this files and folders before. I dont know exactly when i lost the access because i dont access 20.000 files daily and check if they work. So i cant tell you when that happened. probably with one of the latest OC updates/upgrades.
All the files were in the database and I had access before. now i lost it to certain files. I cant get it back with manually creating the folder, because its already in the database that I (the one and only user of this installation) have no access to it. I think it needs to be fixed in the database rather than the actual filesystem on the server itself.
I had access to ALL my files and folders before and now I got restricted for whatever reason.
I started my owncloud by moving folders from an existing folder outside of OC wiht all my files into the OC data dir and OC created the database for all the files by itself. It worked perfectly and I had access to all the files on my OC. Now i have restrictions on certain files and folders. Well mainly the folder, because all the files are in a directory which I cant access anymore. So basically I just lost permission to see certain folders (including the files located within.)
Is there a manual way to reset the hole file cache or database to tell OC to start from scratch...
Thanks for that clarification. To put files manually via FTP into the data-folder is done by many users and statements like this
ring all alarm bells 
Normally, that should not happen at all, default charset of php and mysql should be set to utf8. Could be related to your problem. It is difficult to find out the reason what has happened, perhaps a timeout (php, database)?
Yes with a new setup. The problem is you can't trigger a filescan, but even if you could, this would create a complete new file index, meaning all your sharing settings, file tags, .. are lost and the client needs to download all files again!
Running ownCloud on shared hosting comes with certain limitations. There were already thoughts about dropping the support completely: https://central.owncloud.org/t/drop-support-for-shared-hosting-installations-where-no-shell-access-is-available/930/12
Especially if you use a larger setup, I would recommend moving to a more suitable environmet, at least a vserver or some device at home (RPi3, Intel NUC, ...).
Hi tflidd,
thanks for your message. I dont care if I loose share settings, tags and so on. I am using OC as an easy way to access files from everywhere and everything.
Well this is the most suitable enviroment for me, because I have unlimited storage and I wont get that with any vserver or anything else. At least nothing I have found so far. Thats why my current setup is best for me. I dont need the performance for a lot of users. Its a single user system, sometimes I share some files and "delete" the share link again
About your timeout, that could be, but I dont know. But the timeout shouldnt matter, because the folders I can't access are already indexed or were indexed before.
Now my OC installation is kinda useless, if i cant access all the files.
The only way is to figure out, up to which size your webhosting can handle a owncloud installation. If you find any pattern why and when the file-index gets wrong, we can try to track the problem.
You can setup a new installation, only other way to fix it, you could migrate the whole setup to a local machine, run the repair commands, and then migrate it back to your webhoster.
If i set up a new installation on the server, can I somehow "move" my current data fodler to the new directory without uploading it again?
You can set your old storage-location as external storage and then copy the files.
hey, can you give me some more insights on that? so link another owncloud installation with the new owncloud?
or just change the data dir in the config file to my current location?
I would create a new setup with a new data-directory since ownCloud doesn't like if you make changes to the data-folder yourself. The external storage feature can include other folders on your filesystem.
Hmm this doesnt really help me either. I tried many times to set up external storages or even link to another owncloud installation on a different server.
the loading time was crazy long. took like 2 minutes or longer to establish a connection to the remote OC then if i clicked any folder i hat to wait another 2 minutes or more.
If i access the owncloud installation individually they were super fast and no problems 
There must be any solution for this issue. How can I even lose access to files I always had access too...
So if i have a new owncloud installation and then point the datadir to an external folder (not in the owncloud installation root dir) I will get issues again, because there are already files in this folder? Its about 60-70gb on files. and a lot of files which would take forever to download and upload.
Hmm will do,
but I guess it wont give me access to my files again. This is a nightmare, now I have to download everything and reupload? Thats just a great waste of time and resources...
Oh boy...
If it is really a bug, the fix should bring you back your files.
Running owncloud in hosted environments can be a nightmare, in some cases it seems to work fairly well but you fully depend your hoster's settings.
Hi tfidd,
which fix? the one i cant use because my hoster doesn't allow it? thats not a fix I can use.
Owncloud worked great for me the last ~ 4 years. never had an issue...
I see hosted environment as an issue for a multi user setup with a lot of transfers...I dont have that.
Shared hosters environments are always an issue, even with single users. We can discuss this to death in here but it won't solve your issue.
If you're loosing access to your files without doing any modifications within the datadir report it to the bugtracker as already described. Everything else doesn't make any sense so i'm closing here.
With fix I just meant, that if you report an issue on github, they will come up with a solution (called a "fix"). So there is no fix yet, we don't even know where the real problem is.