Hi,
I have installed Nextcloud 12 on my Ubuntu Server 16.04 and first everything was working fine. I could create folders from the UI, upload files and even upload files from the android client. I only had a “minor” problem: When I tried to open a shared link, I received an Internal Error. I have described the error in more detail here: https://help.nextcloud.com/t/13141
I thought that maybe a reboot would fix the problem, but it only made things worse. Now I get a similar error right after the login. That means that I can see the login screen, enter my credentials, get redirected to “/apps/files” and instead of seeing the homepage, I get the same “Internal Server Error” message. This time the logs are a bit different though. I still get a “NotPermittedException”, but now on a delete operation. I have looked at the filesystem and already executed “chown -R www-data:www-data” on my web folder as well as data folder. So I assume that the filesystem should be fine.
I have also looked into the logs and tried to do some debugging, but since I am not really a PHP expert, this is all could find so far:
As stated in the logs, the exception is thrown by the delete operation in the file SimpleFile.php. The exception however is actually thrown inside File.php. Here the permissions are validated, which fails and thus the exception is thrown. I have looked into the data that is used for the validation and its origin is the $data attribute inside the file FileInfo.php. I have written the content into the logs using $logger->debug(data[‘permissions’]); and the value that was logged was simply “d”.
I am stuck at this point as the $data attribute is injected into the class and I don’t know where this actually happens. I assume its done using the composer component, but I don’t really know how this works. Therefore I would really appreciate your help!
I have even formatted the log… 
==================
{“reqId”:“vLzCNXWpL6QVtCAUwD3u”,
“level”:3,“time”:“2017-05-28T11:33:57+00:00”,
“remoteAddr”:“xxx”,
“user”:“nextcloud”,
“app”:“core”,
“method”:“GET”,
“url”:"/nextcloud/index.php/apps/files/",
“message”:“Exception: {“Exception”:“OCP\Files\NotPermittedException”,
“Message”:”",
“Code”:0,“Trace”:"#0 /var/www/nextcloud/lib/private/Files/SimpleFS/SimpleFile.php(107): OC\Files\Node\File->delete()
\n#1 /var/www/nextcloud/lib/private/Template/SCSSCacher.php(252): OC\Files\SimpleFS\SimpleFile->delete()
\n#2 /var/www/nextcloud/lib/private/Template/SCSSCacher.php(164): OC\Template\SCSSCacher->resetCache()
\n#3 /var/www/nextcloud/lib/private/Template/SCSSCacher.php(109): OC\Template\SCSSCacher->variablesChanged()
\n#4 /var/www/nextcloud/lib/private/Template/CSSResourceLocator.php(99): OC\Template\SCSSCacher->process(’/var/www/nextcl…’, ‘core/css/server…’, ‘core’)
\n#5 /var/www/nextcloud/lib/private/Template/CSSResourceLocator.php(56): OC\Template\CSSResourceLocator->cacheAndAppendScssIfExist(’/var/www/nextcl…’, ‘core/css/server…’)
\n#6 /var/www/nextcloud/lib/private/Template/ResourceLocator.php(75): OC\Template\CSSResourceLocator->doFind(‘css/server’)
\n#7 /var/www/nextcloud/lib/private/TemplateLayout.php(225): OC\Template\ResourceLocator->find(Array)
\n#8 /var/www/nextcloud/lib/private/TemplateLayout.php(170): OC\TemplateLayout::findStylesheetFiles(Array)
\n#9 /var/www/nextcloud/lib/private/legacy/template.php(205): OC\TemplateLayout->__construct(‘user’, ‘files’)
\n#10 /var/www/nextcloud/lib/public/AppFramework/Http/TemplateResponse.php(157): OC_Template->fetchPage()
\n#11 /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php(113): OCP\AppFramework\Http\TemplateResponse->render()
\n#12 /var/www/nextcloud/lib/private/AppFramework/App.php(114): OC\AppFramework\Http\Dispatcher->dispatch(Object(OCA\Files\Controller\ViewController), ‘index’)
\n#13 /var/www/nextcloud/lib/private/AppFramework/Routing/RouteActionHandler.php(47): OC\AppFramework\App::main(‘ViewController’, ‘index’, Object(OC\AppFramework\DependencyInjection\DIContainer), Array)
\n#14 [internal function]: OC\AppFramework\Routing\RouteActionHandler->__invoke(Array)
\n#15 /var/www/nextcloud/lib/private/Route/Router.php(299): call_user_func(Object(OC\AppFramework\Routing\RouteActionHandler), Array)
\n#16 /var/www/nextcloud/lib/base.php(1000): OC\Route\Router->match(’/apps/files/’)
\n#17 /var/www/nextcloud/index.php(40): OC::handleRequest()
\n#18 {main}",
“File”:"/var/www/nextcloud/lib/private/Files/Node/File.php",
“Line”:122}",
“userAgent”:“Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36”,
“version”:“12.0.0.29”}
Thanks in advance!
