Attachment file locked

Hello experts

I have a trouble when I attached some file to SM web client

After that I attach the file I delete the file from the source folder and after I add another one with the same name like that attached and appears an error:

"The file already exist"

These happens when I have the Service Manager web client session is open

It´s look like the SM locks the file or maybe the file could not be completely uploaded yet

With another computer works normally

Do you have some idea to resolve these? Please

Thanks in advance

Best regards