There is no direct way to export the Library to excel, but you can run the Library Resource report and save it as a text file for each section in turn, these can then be opened in Excel.
The steps to do this are as follows:
Run the Reports, Library, Library Resource Report
Select the Resource Headings (They are exported section by section, Material Headings are all reported on separately)
Change the Output function to Text File, Save the file
Open Excel
Go to File, Open
Change to search for all file types then locate the text file.
Follow the steps for the import wizard, putting the column breaks in appropriate places - scroll down to ensure that this is correct.
You will now have the data in an Excel format, but you must save it to keep it as such.
Note: An amended excel file cannot be imported back in to the software. Changes to the library are made one at a time when using the correct password.