If a keychain error message is displayed on the screen when using Slapshot in a remote access environment, please try the following measures.
It is possible to perform this from your home, laboratory, etc.
Login to WebDAV in the Mac environment and delete the keychain file.
Login interface for WebDAV: https://davm01.ecc.u-tokyo.ac.jp/ or https://davm02.ecc.u-tokyo.ac.jp/
Target directory: ~/Library/Keychains
Delete the keychain directory under the Library directory.
Please see the following web page for details on the WebDAV environment.
https://www.ecc.u-tokyo.ac.jp/en/webdav.html
Once you have completed the above step, please check to see whether or not the keychain error message is displayed.