Intermittent : The term 'get-date' is not recognized as the name of a cmdlet, function, script file, or operable program.

Question

I have developed a batch harness whereby all scheduled tasks (W2012) invoke a common powershell script that acts as a wrapper to all our housekeeping jobs.
The first step in the wrapper is to create a Transcript file using following code
if ($Host.name -ne "Windows PowerShell ISE Host") # Transcript does not work within ISE
$timestamp = (get-date -format "yyyy-MM-dd-HH-mm-ss.fff")
$path = "c:\corp\$timestamp" + "_$pid.txt"
Start-Transcript -path $path -append
As expected the folder contains files with timestamp & pid in name
08/08/2013  11:00 AM            14,388 2013-08-08-11-00-01.158_1620.txt
08/08/2013  11:00 AM            12,506 2013-08-08-11-00-01.485_936.txt
08/08/2013  11:00 AM            12,994 2013-08-08-11-00-01.735_9328.txt
08/08/2013  11:00 AM            12,024 2013-08-08-11-00-01.766_8624.txt
08/08/2013  11:00 AM            13,902 2013-08-08-11-00-01.860_1756.txt
08/08/2013  11:01 AM            15,142 2013-08-08-11-01-31.392_10120.txt
08/08/2013  05:00 AM            14,982 _1692.txt
However note the last file, it has a zero length date time value in the name
The error recorded by PowerShell is
get-date : The term 'get-date' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At C:\Corp\Powershell\DMPRun-ScheduledTask.ps1:171 char:18
+    $timestamp = (get-date -format "yyyy-MM-dd-HH-mm-ss.fff")
+                  ~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (get-date:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException
IE get-date has failed and returned a zero length field as the timestamp
Can anyone think of a good reason why get-date would fail intermittently?
Do I have to code defensively for base Powershell functions?

Answer 1

I implemented David's suggestion and now I intermittently get
import-module : Access to the path 'PowerShell_CommandAnalysis_Lock' is denied.
At D:\temp\loop_jc2_2013_11_25_08_55_02.ps1:15 char:1
+ import-module Microsoft.Powershell.Utility
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Import-Module], UnauthorizedA
   ccessException
    + FullyQualifiedErrorId : System.UnauthorizedAccessException,Microsoft.Pow
   erShell.Commands.ImportModuleCommand
I added a trap chain (My Powershell skills do not yet include recursive trap coding, any suggestions welcome)
trap {
    trap {
        "Trap1"
        "Exception: " + $_
        "Error: " + $Error[0]
        "Message: " + $_.Exception.Message
        "InnerException: " + $_.Exception.InnerException
        "StackTrace: " + $_.Exception.StackTrace
        "FailedItem: " + $_.Exception.ItemName
        import-module Microsoft.Powershell.Management
        import-module Microsoft.Powershell.Security
        import-module Microsoft.Powershell.Utility
    "Trap2"
    "Exception: " + $_
    "Error: " + $Error[0]
    "Message: " + $_.Exception.Message
    "InnerException: " + $_.Exception.InnerException
    "StackTrace: " + $_.Exception.StackTrace
    "FailedItem: " + $_.Exception.ItemName
    import-module Microsoft.Powershell.Management
    import-module Microsoft.Powershell.Security
    import-module Microsoft.Powershell.Utility
import-module Microsoft.Powershell.Management
import-module Microsoft.Powershell.Security
import-module Microsoft.Powershell.Utility
trap {
    "Trap3"
    "Exception: " + $_
    "Error: " + $Error[0]
    "Message: " + $_.Exception.Message
    "InnerException: " + $_.Exception.InnerException
    "StackTrace: " + $_.Exception.StackTrace
    "FailedItem: " + $_.Exception.ItemName
    exit 1
get-date
Now I intermittently get ..
Trap2
Exception: Access to the path 'PowerShell_CommandAnalysis_Lock' is denied.
Error: Access to the path 'PowerShell_CommandAnalysis_Lock' is denied.
Message: Access to the path 'PowerShell_CommandAnalysis_Lock' is denied.
InnerException:
StackTrace:    at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.Threading.Mutex.MutexTryCodeHelper.MutexTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.Mutex.CreateMutexWithGuaranteedCleanup(Boolean initiallyOwned, String name, Boolean& createdNew, SECURITY_ATTRIBUTES secAttrs)
   at System.Threading.Mutex..ctor(Boolean initiallyOwned, String name, Boolean& createdNew, MutexSecurity mutexSecurity)
   at System.Threading.Mutex..ctor(Boolean initiallyOwned, String name, Boolean& createdNew)
   at System.Management.Automation.AnalysisCache.CacheExportedCommands(PSModuleInfo module, Boolean force, ExecutionContext context)
   at Microsoft.PowerShell.Commands.ModuleCmdletBase.LoadUsingModulePath(PSModuleInfo parentModule, Boolean found, IEnumerable`1 modulePath, String name, SessionState ss, ImportModuleOptions options, ManifestProcessingFlags manifestProcessingFlags,
PSModuleInfo& module)
   at Microsoft.PowerShell.Commands.ImportModuleCommand.ImportModule_LocallyViaName(ImportModuleOptions importModuleOptions, String name)
   at Microsoft.PowerShell.Commands.ImportModuleCommand.ProcessRecord()
   at System.Management.Automation.CommandProcessor.ProcessRecord()
FailedItem:
import-module : Access to the path 'PowerShell_CommandAnalysis_Lock' is denied.
At D:\temp\loop_jc2_2013_11_25_09_19_52.ps1:26 char:1
+ import-module Microsoft.Powershell.Security
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Import-Module], UnauthorizedA
   ccessException
    + FullyQualifiedErrorId : System.UnauthorizedAccessException,Microsoft.Pow
   erShell.Commands.ImportModuleCommand