I can't think of any known Asset scan issues, what version of Protect are you using?
Have you recently made GPO settings to lock down your Windows 7 machines? Asset Scan Requirements
Do Patch scans work?
You could take a look at the logs and look for obvious errors, I would suggest scanning a single machine to make looking at the logs easier.
The logs are located here: C:\ProgramData\LANDESK\Shavlik Protect\Logs (deleting the current logs makes it easier to view the logs)
The Asset scan information would be in the ST.Protect.managed.UserName@ProtectServerName.log
This is a successful Asset Scan: (enable All logging in Tools > Options > Logging before testing)
ResolvableMachine.cs:233|Resolved by machine name 'CWINNINGTest' - 10.x.x.x.
ResolvableMachine.cs:313|Machine name: CWINNINGTest, hostname: CWINNINGTest, NetBIOS name: CWINNINGTest, IP address: 10.X.X.X, name or address: CWINNINGTest, FQDN: CWINNINGTest.localdomain, domain: SHAVLIK ping: 00:00:00.2537905.
PatchAndAssetResolver.cs:119|Scan id = aa313ea4-9ee3-4c7b-bdae-4fd5a60e66bb, Total = 1, Duplicates = 0, Filtered = 0, Excluded = 0
ScanManagerService.cs:74|Asset scan started aa313ea4-9ee3-4c7b-bdae-4fd5a60e66bb
ScanItemsController.cs:162|Scan 'aa313ea4-9ee3-4c7b-bdae-4fd5a60e66bb' complete.
TaskbarNotification.cs:175|Asset scan results ready from scan at 10/18/2016 7:34:57 AM.
WorkItemController.cs:410|Asset scan ended with status: 'Completed'
OperationPresenter.cs:273|Completed ST.UI.Controllers.Scheduling.AssetScan operation: CWINNINGTest
TaskbarNotification.cs:175|1 new scan result(s) are available.
We are running version 9.2.0 build 5119. Have not tried patch scan yet. Will take a look at logs and report back. Thank you