File Permission / Read-only Attributes

Good day, I trust that you are well.
I need advise please. The company who I worked for has purchase My Cloud Home. We are a small accounting firm. We have loaded documents and files onto My Cloud Home. We can access all the files expect for our Pastel Partner files and Case ware files. When we map the program to My Cloud Home, we get an Pervasive Error code, which means the file is unreadable. We checked the properties settings and saw that is set on read-only. We tried to remove the read-only attributes, but no luck. Is there another way how we can remove the read-only attributes or change file permission?
Thank you in advance