Dektop Client crash when local folder has no read/write permissions (cfapi)

[iHerrmann77]

Actual behaviour

When i add a folder sync connection without permissions to that folder, the sync client crashes.

Expected behaviour

When i type or choose the path to that folder, check permissions before I am able to select the owncloud and "Add sync connection" with any kind of error-message

ownCloud 2.7.0v270rc1 (build 2254) ec4341 Oct 9 2020 06:15:11
Libraries Qt 5.12.9, OpenSSL 1.1.1g 21 Apr 2020
Using virtual files plugin: wincfapi

crash-report
fbbf6656-f09a-4151-8309-7c3f7b3b7294

logfile
[ info sync.networkjob.lscol ]: LSCOL of QUrl("https://demo.owncloud.com/remote.php/dav/files/demo/") FINISHED WITH STATUS "OK"
[ debug sync.networkjob ] [ OCC::AbstractNetworkJob::slotFinished ]: Network job OCC::LsColJob finished for ""
[ info gui.account.settings ]: Folder wizard completed
[ info sync.utility ]: Creating "C:/Folder1/Folder2/Folder3//Desktop.ini" to set a folder icon in Explorer.
[ warning default ]: QIODevice::write (QFile, "C:\Folder1\Folder2\Folder3\Desktop.ini"): device not open
[ warning default ]: QIODevice::write (QFile, "C:\Folder1\Folder2\Folder3\Desktop.ini"): device not open
[ warning default ]: QIODevice::write (QFile, "C:\Folder1\Folder2\Folder3\Desktop.ini"): device not open
[ info sync.utility ]: Creating favorite link from "C:/Folder1/Folder2/Folder3/" to "C:/Users/tester/Links/Folder3.lnk"
[ warning sync.database ]: Could not find a writable database path "C:/Folder1/Folder2/Folder3/.sync_8da9d25ef3ff.db" "Access is denied."
[ info plugins ]: Created VFS instance from plugin "owncloudsync_vfs_win"
[ info sync.database ]: Detected filesystem "NTFS" for "C:/Folder1/Folder2/Folder3/.sync_8da9d25ef3ff.db"
[ debug gui.folder ] [ OCC::Folder::checkLocalPath ]: Checked local path ok
[ info sync.configfile ]: Adding system ignore list to csync: "C:/Program Files/ownCloud/sync-exclude.lst"
[ warning sync.vfs ]: Could not check for or unregister previous StorageFolder for "C:\Folder1\Folder2\Folder3" "Element not found."
[ warning sync.vfs ]: Error registering StorageProvider for "C:\Folder1\Folder2\Folder3" "Access is denied."
[ fatal default ]: CfConnectSyncRoot: C:\Folder1\Folder2\Folder3 error: WindowsError: -2147024891: Access is denied.