After fresh install the Mac OS X Lion, when I tried to download again my purchased mac apps with App Store, I found that they are checked as installed.
How can I reinstall my paid apps?
In essence, unmount the volumes with those apps and the App Store will let you download things.
I noticed after the upgrade to lion when my TM volume was connected some apps in the app store appeared to be already installed. So try to disconnect or shut off your external HDD and restart the app store so you can reinstall your apps. After that you can re-activate your TM volume. This isn't normal, since spotlight shouldn't look inside the backup volume and see an app installed, but it happened once so it could happen to you as well.
The problem is there because Spotlights finds Apps on other Partitions and flag them as installed. There are two ways to get that solved. First you delete the lsregister by launching Terminal and pasting this command:
If that won't help, then unmount the Volume where the Apps are installed, Time Machine Volumes also count from previous/other OS installations.
First you need to find out the GUID of the partition:
Launch Disk Utility, click the Partition and then the Info button in left upper corner. Your GUID should look be something like
Thats vi editor specially for your
The line should look like this:
Reboot the OS, check App Store and voilà, you can reinstall your Apps.
After that reedit the