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With older discs, such as older program installation or data file discs, there's NO problem. Something is wrong with newer discs. If I try to access these I either get an error or the disc shows 100% used space. These same discs in the same drive are OK with the Host. Please help & thanks.

CD-ROMs are read only, that's what "ROM" means. So, they'll always show as full.

No-one else is reporting CD reading issues. But, you still might find ISO images of same more reliable.