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Corrupted UI or strange colors

Ensure you are running the latest driver for your graphics adapter.

Handling SSL errors like "unable to find valid certification path to requested target"

FolderSync Desktop uses an application specific trust store. This can cause issues on networks with SSL inspection. For FolderSync Desktop to work on such networks you would need to add your networks custom root CA to the applications trust store. If you are an end user, you can get the custom root CA certificate for your organization from your administrator.

Adding the CA can be done using command:

keytool -import -trustcacerts -alias customrootca -file customrootca.der -keystore <path to FolderSync Desktop cacerts>

To convert a .crt certificate to DER format, use the command:

openssl x509 -in <filename.pem> -inform pem -out <filename.der> -outform der

The cacerts file for FolderSync Desktop can typically be found here:

OS Path
Windows C:\Program Files\WindowsApps\FoldersyncDesktop_1.1.0.0_x64__6t9j0n6a0fbtj\lib\cacerts
MacOs /Applications/FolderSync
Linux (Ubuntu deb) /usr/lib/tacit-dynamics-aps/foldersync-desktop/lib/runtime/lib/security/cacerts

Port 49734 is unavailable, but Windows say it's not in use?

On Windows a port may be reserved, even if it is not in use.

See reserved ports using this command:

netsh int ipv4 show excludedportrange protocol=tcp

A possible fix is to run the commands below. This might cause you to lose internet connection until rebooting. It should free up reserved ports and add the Foldersync Desktop port to the excluded range so it will no longer be reserved by winnat.

net stop winnat
net start winnat
netsh int ipv4 add excludedportrange protocol=tcp startport=49734 numberofports=1