Foreach write output when one or more fail - powershell

Question

Currently I have this script:
$AdminSiteURL="https://contoso-admin.sharepoint.com"
$SiteURL=""
$UserID="klaas.hansen#contoso.nl"
$sitecollectios = #("https://contoso.sharepoint.com/sites/Extranet","https://contoso.sharepoint.com/sites/contoso","https://contoso.sharepoint.com/sites/Projecten","https://contoso.sharepoint.com/sites/PFO","https://contoso.sharepoint.com/sites/beheer","https://contoso.sharepoint.com/sites/Intranet")
#Get Credentials to connect
$Cred = Get-Credential
#Connect to SharePoint Online Admin Site
Connect-SPOService -Url $AdminSiteURL -Credential $cred
foreach ($collectie in $sitecollectios)
{
Get-SPOUser -Site $collectie -LoginName $UserID
}
When it can't find the user however the foreach shows an error. which is obvious. Is it possible to when it can't find the user in one or more of the site collections it shows me an error in write output, but not every time it can't find it. so for example it can't find the user in 3 site collections it only has to show me once that it can't find it.

Answer 1

Mathias R. Jessen's solution is effective, but there's a simpler and faster alternative:
The -ErrorVariable common parameter has a rarely seen feature that allows you to append the errors collected during command execution to an existing variable, simply by prepending + to the target variable name, which enables the following solution:
foreach ($collectie in $sitecollectios)
{
# Using built-in alias parameter names, you could shorten to:
# Get-SPOUser -ea SilentlyContinue -ev +errs ...
Get-SPOUser -ErrorAction SilentlyContinue -ErrorVariable +errs -Site $collectie -LoginName $UserID
}
# Print the errors that occurred.
$errs
-ErrorAction SilentlyContinue silences the errors (do not use Ignore, as that would suppress the errors altogether).
-ErrorAction +errs collects any error(s) in variable $errs, by either appending to the existing collection in $errs or by creating one on demand.
Note how the variable name, errs must not be prefixed with $ when passed to -ErrorAction.
Afterwards, you can examine the $errs collection to see for which users the call failed.
$errs (like the automatic $Error variable that collects errors session-wide) will be an array-like object (of type System.Collections.ArrayList) containing System.Management.Automation.ErrorRecord objects.
The simplest way to get the error message (short of simply printing $errs as a whole to the screen) is to call .ToString() on an error record; e.g., $errs[0].ToString(); to get all error messages in the collection, use $errs.ForEach('ToString'). There is the .Exception.Message property, but that can situationally be overruled by .ErrorDetails.Message when the error prints to the display; .ToString() applies this logic automatically.
The .TargetObject property tells you the target object or input that triggered the error; I can't personally verify what Get-SPOUser does, but it would make sense for the -LoginName argument of a non-existing users to be reflected there; this is how it works analogously with Get-Item -Path NoSuch, for instance: in the resulting error record, .TargetObject contains 'NoSuch' resolved to a full path.

Answer 2

Catch the errors inline and then report on number of errors caught at the end:
$FailedCollections = #()
Connect-SPOService -Url $AdminSiteURL -Credential $cred
foreach ($collectie in $sitecollectios)
{
try{
Get-SPOUser -Site $collectie -LoginName $UserID -ErrorAction Stop
}
catch{
$FailedCollections += $collectie
}
}
if($FailedCollections.Count -ge 1){
Write-Error "Errors encounted in $($FailedCollections.Count) collections: [$($FailedCollections -join ', ')]"
}