Import of several RIS files

I have several RIS files with around 10-60 entries I wanted to import. These RIS files were created with the same EndNote version I am using for the import. The import of the first RIS file works just fine by double clicking the file or by the import function. But trying to import the second file directly after the first one gives me an error message: “Data base error. Please verify that no other user has this library open simultaneously with write access.” Since the library and RIS files are on my desktop and I’m not sharing this library this is definitely not the case. There is a work around to this problem but I’d rather like to be able to import directly one after the other. Is there a fix for this?

Thanks and kind regards
Stephanie