Ondrej Žilinec – IT Blog

Last week I was playing with application virtualization. I do have experiences with VMWare Thinapp applications. I already did couple of those virtualized applications. When I was forced to use App-V to create virtualized application I needed to make one application and I needed make this application to write registries into real registries and not to virtual ones. I thought it would be same as in VMWare Thinapp. That means I would expect to set some “isolation” mode on registry branch.

Problem is that you can define only two modes in App-V for registries:

• Merge with Local Key – This will merge real registries with virtual ones. Change will be written into virtual registries.
• Override Local Key – This will show only virtual registries to application and changes will be written into virtual registries.

In VMWare Thinapp there are isolation modes (for file system structures and also for registries) defined as following:

• Full – Real are not shown. Any modification goes into virtual. New elements go into virtual.
• Merged – Real are shown. Modification of virtual goes to virtual. Modification of real goes to real. New elements go to real.
• WriteCopy – Real are shown. Modification of virtual goes to virtual. Modification of real goes to virtual. New elements go to virtual.

In VMWare Thinapp you can define each file/directory/registry’s isolation mode.

If you want to exclude registries from virtualization, it means you want to write modifications into real registries, you need to change App-V client settings in its registries. In branch:

HKLM\\SOFTWARE\\Wow6432Node\\Microsoft\\SoftGrid\\4.5\\SystemGuard\\Overrides

there are two values:

• VirtualRegistryPassthrough – used to allow a local process pass up into the virtual Registry.
• VirtualRegistryPassthroughEx – It can be used to ensure a specific key will always pass through to the real registry.

So if you want your App-V application write changes to real registries for example to HKLM\\Software\\TEST01 you need to add string “HKLM\\Software\\TEST01” into REG_MULTI_SZ key called VirtualRegistryPassthroughEx.

This is really not very ideal way. It would be similar to VMWare, because it’s better solution.