PowerShell: Cannot bind argument to parameter 'Path' because it is null.

Cannot bind argument to parameter 'Path' because it is null. means you passed a variable to a parameter that does not accept $null (most mandatory parameters), and the variable was $null at that moment. The variant ... because it is an empty string. means it held ''. The parameter name in quotes tells you which argument was empty; find out why the variable has no value, usually a typo in its name or a lookup that found nothing.

Reproduce it

$ErrorActionPreference = 'Stop'
$file = 'notes.txt'
'hello' | Set-Content $file
try { Get-Content -Path $fiel } catch { $_.Exception.Message; '  -> ' + $_.FullyQualifiedErrorId }
try { Get-Content -Path '' } catch { $_.Exception.Message }
$latest = Get-ChildItem -Filter *.log | Select-Object -First 1
try { Remove-Item -Path $latest.FullName } catch { $_.Exception.Message }
Get-Content -Path $file

Cannot bind argument to parameter 'Path' because it is null.
  -> ParameterArgumentValidationErrorNullNotAllowed,Microsoft.PowerShell.Commands.GetContentCommand
Cannot bind argument to parameter 'Path' because it is an empty string.
Cannot bind argument to parameter 'Path' because it is null.
hello

$fiel is a typo, so it is undefined and therefore $null. $latest is $null because no .log file exists, and so is $latest.FullName.

Catch it earlier

Strict mode turns the typo into an error on the line that uses it:

Set-StrictMode -Version Latest
try { Get-Content -Path $fiel } catch { $_.Exception.Message }

The variable '$fiel' cannot be retrieved because it has not been set.

In your own functions and scripts, declare what you need so the caller gets a clear error:

param(
    [Parameter(Mandatory)]
    [ValidateNotNullOrEmpty()]
    [string] $Path
)

With Mandatory, an interactive caller is prompted for the value; in a non-interactive run (powershell -NonInteractive, CI, scheduled tasks) a missing mandatory parameter is an error instead of a prompt.

Common sources of $null