Upgraded Nextcloud, now after login I get an error

As title says, I updated NC from within the site itself, and now after login I get the following message. It appears its peeved about a missing file. How can I decipher where its supposed to go? I can do a dummy file and plop it in, or if there is some information as to why this error is occuring, I can kill the addon/enable the addon. There were in fact three addons that were disabled for the update. If that is the issue, how can I manually re-enable them, as I cannot get into the application to do so the “normal” way.

Thanks,
Nextcloud noob here, just started using it and this is the first upgrade, and also first issue.

Andrew.

{"reqId":"WFRi6JIJaW2eDfxPIbs3YAAAAAs","remoteAddr":"redacted","app":"index","message":"Exception: {\"Exception\":\"RuntimeException\",\"Message\":\"image not found: image:mail_cloud.png webroot:\\\/nextcloud serverroot:\\\/var\\\/www\\\/html\\\/nextcloud\",\"Code\":0,\"Trace\":\"#0 \\\/var\\\/www\\\/html\\\/nextcloud\\\/apps\\\/external\\\/appinfo\\\/app.php(38): OC\\\\URLGenerator->imagePath('external', 'mail_cloud.png')\\n#1 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/NavigationManager.php(64): OC_App::{closure}()\\n#2 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/legacy\\\/app.php(717): OC\\\\NavigationManager->getAll()\\n#3 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/TemplateLayout.php(83): OC_App::getNavigation()\\n#4 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/legacy\\\/template.php(228): OC\\\\TemplateLayout->__construct('user', 'files')\\n#5 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/public\\\/AppFramework\\\/Http\\\/TemplateResponse.php(157): OC_Template->fetchPage()\\n#6 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/AppFramework\\\/Http\\\/Dispatcher.php(113): OCP\\\\AppFramework\\\\Http\\\\TemplateResponse->render()\\n#7 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/AppFramework\\\/App.php(111): OC\\\\AppFramework\\\\Http\\\\Dispatcher->dispatch(Object(OCA\\\\Files\\\\Controller\\\\ViewController), 'index')\\n#8 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/AppFramework\\\/Routing\\\/RouteActionHandler.php(47): OC\\\\AppFramework\\\\App::main('ViewController', 'index', Object(OC\\\\AppFramework\\\\DependencyInjection\\\\DIContainer), Array)\\n#9 [internal function]: OC\\\\AppFramework\\\\Routing\\\\RouteActionHandler->__invoke(Array)\\n#10 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/Route\\\/Router.php(293): call_user_func(Object(OC\\\\AppFramework\\\\Routing\\\\RouteActionHandler), Array)\\n#11 \\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/base.php(983): OC\\\\Route\\\\Router->match('\\\/apps\\\/files\\\/')\\n#12 \\\/var\\\/www\\\/html\\\/nextcloud\\\/index.php(48): OC::handleRequest()\\n#13 {main}\",\"File\":\"\\\/var\\\/www\\\/html\\\/nextcloud\\\/lib\\\/private\\\/URLGenerator.php\",\"Line\":196}","level":3,"time":"2016-12-16T21:55:52+00:00","method":"GET","url":"\/nextcloud\/index.php\/apps\/files\/","user":"andrew","version":"9.1.2.2"}

image is called main_cloud.png and should go into (probably) the files_external app (maybe files_externa/img)

Thanks for the prompt reply Bernhard!

Unfortuantely the two spots werent it. I actually am thinking, this file may be a custom icon I found for one of the apps. Where would the custom app icons be normally placed? I think this may just be one of many errors if those files are missing entirely. I think if this is the case that there would be about 6 or so images that should be there.