Thanks for your reply. Font installation is correct. I have this problem with my new 16" macbook pro with catalina system (which only support CC2019 & CC2020). I tried in another two iMacs with Mac os High Sierra & Mojave with different versions of indesign including cc19 & 20. They all are working fine. I am worried that, is there any arabic compatibility issue with new mac os and indesign. All my files are in cs3 version and I can not open them in new laptop. Please help me to find out a solution for this..