All my events are disappeared. When I make a new event, Lightning does'nt show it, but the event appears in the Google Agenda. When I make an event in Google Agenda it does'nt appear in Lightning.

I solved the problem by uninstall and install Thunderbird; first I saved all my email by: I installed in Thunderbird the addon ImportExportTool and with this tool I did an export of all the email: "Export folder with subfolders (with structure)" and stored it on my pc. Then I did an uninstall of Thunderbird and after that with Windows Explorer I deleted all the subfolders and files from "C:\Users\<user>\AppData\Roaming\Thunderbird" and restarted the pc. Then I installed Thunderbird again; by making the new email account(s) I chose for POP instead off IMAP. When you have more email accounts make them in the same order as you had them in Thunderbird before. Then I closed Thunderbird. With Windows Explorer I copied the folders and files from the stored email to "C:\Users\<user>\AppData\Roaming\Thunderbird\Profiles\<aaaa>.default\Mail": in the Mail folder you see "Local Folders" and "pop.googlemail.com" and by more email addresses "pop.googlemail1.com", etc. In this subfolders I deleted first the subsubfolders and files; then I copied the subfolders and files from the stored email. Now all email was back in Thunderbird and then I installed the addons for "Lightning", "Google Contacts" and "Provider" for Google Agenda". Then the Lightning agenda was again working with Google-agenda.