How to uninstall the Atera agent by Powershell Script 

https://support.atera.com/hc/en-us/articles/5849002658844-How-do-I-remove-the-Atera-Agent-after-my-trial-has-expired

Regarding your query, what I would recommend, after you rename the PC, make sure to reboot it.  

After that, I would recommend to run the following script using PowerShell ISE as admin, locally :  

https://support.atera.com/hc/en-us/articles/5849002658844-How-do-I-remove-the-Atera-Agent-after-my-trial-has-expired

Once the script is finished, reboot the device again. In order for the registry keys to be removed / updated, reboot would be needed.  

After this, I would recommend using the CMD installation method instead of .MSI in order to install Atera Agent and assign it to the right customer. 

Function Get-UninstallCodes ([string]$DisplayName) { 

‘HKLM:SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall’, ‘HKLM:SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall’ | ForEach-Object { 

Get-ChildItem -Path $_ -ErrorAction SilentlyContinue | ForEach-Object { 

If ( $(Get-ItemProperty -Path $_.PSPath -Name ‘DisplayName’ -ErrorAction SilentlyContinue) -and ($(Get-ItemPropertyValue -Path $_.PSPath -Name ‘DisplayName’ -ErrorAction SilentlyContinue) -eq $DisplayName) ) { 

$str = (Get-ItemPropertyValue -Path $_.PSPath -Name ‘UninstallString’) 

$UninstallCodes.Add($str.Substring(($str.Length – 37),36)) | Out-Null 

} 

} 

} 

} 

Function Get-ProductKeys ([string]$ProductName) { 

Get-ChildItem -Path ‘HKCR:Installer\Products’ | ForEach-Object { 

If ( $(Get-ItemProperty -Path $_.PSPath -Name ‘ProductName’ -ErrorAction SilentlyContinue) -and ($(Get-ItemPropertyValue -Path $_.PSPath -Name ‘ProductName’ -ErrorAction SilentlyContinue) -eq $ProductName) ) { 

$ProductKeys.Add($_.PSPath.Substring(($_.PSPath.Length – 32))) | Out-Null 

} 

} 

} 

Function Get-ServiceStatus ([string]$Name) { (Get-Service -Name $Name -ErrorAction SilentlyContinue).Status } 

Function Stop-RunningService ([string]$Name) { 

If ( $(Get-ServiceStatus -Name $Name) -eq “Running” ) { Write-Output “Stopping : ${Name} service” ; Stop-Service -Name $Name -Force } 

} 

Function Remove-StoppedService ([string]$Name) { 

$s = (Get-ServiceStatus -Name $Name) 

If ( $s ) { 

If ( $s -eq “Stopped” ) { 

Write-Output “Deleting : ${Name} service” 

Start-Process “sc.exe” -ArgumentList “delete ${Name}” -Wait 

} 

} Else { Write-Output “Not Found: ${Name} service” } 

} 

Function Stop-RunningProcess ([string]$Name) { 

$p = (Get-Process -Name $_ -ErrorAction SilentlyContinue) 

If ( $p ) { Write-Output “Stopping : ${Name}.exe” ; $p | Stop-Process -Force } 

Else { Write-Output “Not Found: ${Name}.exe is not running”} 

} 

Function Remove-Path ([string]$Path) { 

If ( Test-Path $Path ) { 

Write-Output “Deleting : ${Path}” 

Remove-Item $Path -Recurse -Force 

} Else { Write-Output “Not Found: ${Path}” } 

} 

Function Get-AllExeFiles ([string]$Path) { 

If ( Test-Path $Path ) { 

Get-ChildItem -Path $Path -Filter *.exe -Recurse | ForEach-Object { $ExeFiles.Add($_.BaseName) | Out-Null } 

} 

} 

# Mount HKEY_CLASSES_ROOT registry hive 

New-PSDrive -Name HKCR -PSProvider Registry -Root HKEY_CLASSES_ROOT | Out-Null 

####### 

# START: Information gathering 

####### 

# Get MSI package codes from the uninstall key 

$UninstallCodes = New-Object System.Collections.ArrayList 

‘AteraAgent’, ‘Splashtop for RMM’, ‘Splashtop Streamer’ | ForEach-Object { Get-UninstallCodes -DisplayName $_ } 

# Get product keys from the list of installed products 

$ProductKeys = New-Object System.Collections.ArrayList 

‘AteraAgent’, ‘Splashtop for RMM’, ‘Splashtop Streamer’ | ForEach-Object { Get-ProductKeys -ProductName $_ } 

# Define all the directories we’ll need to cleanup at the end of this script 

$Directories = @( 

“${Env:ProgramFiles}\ATERA Networks”, 

“${Env:ProgramFiles(x86)}\ATERA Networks”, 

“${Env:ProgramFiles}\Splashtop\Splashtop Remote\Server”, 

“${Env:ProgramFiles(x86)}\Splashtop\Splashtop Remote\Server”, 

“${Env:ProgramFiles}\Splashtop\Splashtop Software Updater”, 

“${Env:ProgramFiles(x86)}\Splashtop\Splashtop Software Updater”, 

“${Env:ProgramData}\Splashtop\Splashtop Software Updater” 

) 

# Get all possible relevant exe files so we can make sure they’re closed later on 

$ExeFiles = New-Object System.Collections.ArrayList 

“${Env:ProgramFiles}\ATERA Networks” | ForEach-Object { Get-AllExeFiles -Path $_ } 

# Define a list of services we need to stop and delete (if necessary) 

$ServiceList = @( 

‘AteraAgent’, 

‘SplashtopRemoteService’, 

‘SSUService’ 

) 

# Define a list of registry keys we’ll delete 

$RegistryKeys = @( 

‘HKLM:SOFTWARE\ATERA Networks’, 

‘HKLM:SOFTWARE\Splashtop Inc.’, 

‘HKLM:SOFTWARE\WOW6432Node\Splashtop Inc.’ 

) 

####### 

# END: Information gathering 

####### 

# Uninstall each MSI package code in $UninstallCodes 

$UninstallCodes | ForEach-Object { Write-Output “Uninstall: ${_}” ; Start-Process “msiexec.exe” -ArgumentList “/X{${_}} /qn” -Wait } 

# Stop services if they’re still running 

$ServiceList | ForEach-Object { Stop-RunningService -Name $_ } 

# Terminate all relevant processes that may still be running 

$ExeFiles.Add(‘reg’) | Out-Null 

$ExeFiles | ForEach-Object { Stop-RunningProcess $_ } 

# Delete services if they’re still present 

$ServiceList | ForEach-Object { Remove-StoppedService -Name $_ } 

# Delete products from MSI installer registry 

$ProductKeys | ForEach-Object { Remove-Path -Path “HKCR:Installer\Products\${_}” } 

# Unmount HKEY_CLASSES_ROOT registry hive 

Remove-PSDrive -Name HKCR 

# Delete registry keys 

$RegistryKeys | ForEach-Object { Remove-Path -Path $_ } 

# Delete remaining directories 

#Write-Host “Waiting for file locks to be freed” ; Start-Sleep -Seconds 4 

$Directories | ForEach-Object { Remove-Path -Path $_ }