id,summary,reporter,owner,description,type,status,component,version,resolution,keywords,cc,guest,host 15500,Changing Win10 Guest Drive letter triggers I/O Error,peterg4000,,"I have a secondary virtual Hard disk in my Windows 10 guest under an Arch Linux Host. The secondary drive comes up as E:\ in my guest, but I would like it to be D:\ With the Virtual CD-ROM drive disabled via VBox (Just to simplify things), in the Windows Guest I use the usual Windows 'Disk Management' tool to change the drive letter. There is a standard Windows message about the danger of changing a letter, then when I click ""Yes"" Virtual Box instantly throws an I/O error. Here is the contents from clicking 'Copy' in that VBox error window: {{{ An error has occurred during virtual machine execution! The error details are shown below. You may try to correct the error and resume the virtual machine execution. The I/O cache encountered an error while updating data in medium ""ahci-0-1"" (rc=VERR_DISK_FULL). Make sure there is enough free space on the disk and that the disk is working properly. Operation can be resumed afterwards. Error ID: BLKCACHE_IOERR Severity: Non-Fatal Error }}} I will also attach full vbox log. No, I do not have any full disks anywhere to be seen. I have to virtually power-off the box to recover. The drive is back on E:\ after restart. Is this use-case expected to work under VBox? I can't see why not...",defect,closed,virtual disk,VirtualBox 5.0.20,obsolete,,,Windows,Linux