Virtual drive letter changes. Fix: Copy all DVDs into a single folder on your HDD (e.g., C:\Dialogys_ISOs\DVD1 , DVD2 , etc.). Run setup from that folder and point to subfolders when asked.
when prompted:
⚠️ : Never attempt a Dialogys 4.90 install onto an external USB hard drive or a fragmented network share. The application’s internal relational database relies on fast index queries that fail or time out on slow external media, resulting in missing data structures. Step-by-Step Dialogys 4.90 Installation Guide dialogys 490 install