CorelDraw X6 Save As not working for some files

We are company using Corel X6 product. Some time ago we faced a serious problem that some corel draw files become anable to be saved as, exported, printed to PDF distiller. Wilst they still can be saved to the same name. But due to the working in a group, this same name can be holded by someone else opening the file elswere (without knowing where exactly). So save as, still as export is vital! I've been strugling for monthes with the issue. Discovered that most of the problems are fixed by blocking the ObjectData.xml (marking it as read only). For some files it doesnt work. And the issue is double purging the symbolic links (from the first purge it doesnt work. Purge-save. Open, purge, any change so the save is enabled, save). But some files wont save as even after these workarounds. It is really a stubling block now. Really crusial. I am attaching the file. It will save in 2019 tial version I have. But say, upgrading to a version you do not need because in the one you use the main feature is not working is smth we cannot afford. Furthermore I have tons of VBA macros that I've made for years and they do not work on Corel 2019 because of some command suntaxis change. 

UITT 2020.cdr