I just went through this. Don't use the Import Calendar. It doesn't work. Instead, find a calendar client file that is working. Do an Export Text File and export everything. Then create a new server file (on your replacement computer) with the same name as the old server file. Then try to sync a client calendar with the new server. It will warn you that the server appears to be different, do you want to proceed, you might lose your data. Tell it yes. All you calendar data will disappear. Now at the client calendar do an Import Text File. It will all come in, but the categories are all private and have no color or style. Go to Define Categories and select one of your categories. Notice it is Private. That is a drop down menu, make it Public. Do this for all your public categories. Then go back to Category Styles and make the categories the colors and styles you had before. All this imported data should sync to the new server. Make a copy of the calendar file you have that is fresh and copy it to all the other clients on your network. Before you try all this, make copies of everything. Also disconnect some of your clients so you don't mess up those client calendar files in case things do not go well. I am probably talking to myself here, if this is the last post ever.