Dropbox required update, but update failed and so does clean install

Ok, here is a powershell script I had to create to take out everything dropbox related that was preventing a new install to happen. Use this only after you already uninstalled dropbox, and find that the darn thing wont reinstall... (this happened to me)

Mark this as the solution

<# 
Dropbox Deep-Clean Script (PowerShell)
- Removes stray Dropbox processes, services, scheduled tasks
- Uninstalls registered MSI entries bearing "Dropbox"
- Deletes leftover folders (ProgramData, Program Files (x86), LocalAppData)
- Removes stale Event Log source (DbxSvc) that spams errors
- Produces a summary at the end

Run as Administrator. Tested on Windows 10/11 PowerShell 5/7.
#>

# region: guardrails
$ErrorActionPreference = 'SilentlyContinue'
$ProgressPreference = 'SilentlyContinue'

function Write-Info($msg){ Write-Host "[*] $msg" -ForegroundColor Cyan }
function Write-OK($msg){ Write-Host "[+] $msg" -ForegroundColor Green }
function Write-Warn($msg){ Write-Host "[!] $msg" -ForegroundColor Yellow }
function Write-Err($msg){ Write-Host "[x] $msg" -ForegroundColor Red }

# Admin check
$principal = New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())
if (-not $principal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)) {
  Write-Err "Please run this script as Administrator."
  exit 1
}

# endregion

# region: tracking
$did = New-Object System.Collections.Generic.List[string]

# endregion

# region: kill processes
Write-Info "Stopping Dropbox-related processes (if any)..."
$procs = Get-Process | Where-Object { $_.Name -match '^(Dropbox|DropboxUpdate|Dbx|DbxSvc|DropboxUpdater)' }
if ($procs) {
  $procs | ForEach-Object {
    try { Stop-Process -Id $_.Id -Force -ErrorAction Stop; $did.Add("Stopped process: $($_.Name) [$($_.Id)]") } catch {}
  }
} else {
  Write-Info "No Dropbox-related processes found."
}
# endregion

# region: services
Write-Info "Removing Dropbox-related services..."
# Known names + heuristic match
$svcNames = @(
  'dbupdate','dbupdatem',
  'DropboxUpdate','DropboxUpdater','DropboxUpdaterService',
  'DbxSvc'
)

# Add any service whose Name or DisplayName contains 'dropbox' or 'dbx'
$discover = Get-Service | Where-Object { $_.Name -match 'dropbox|dbx' -or $_.DisplayName -match 'dropbox|dbx' }
$targets = @()
$targets += $svcNames | ForEach-Object { Get-Service -Name $_ -ErrorAction SilentlyContinue }
$targets += $discover
$targets = $targets | Sort-Object Name -Unique | Where-Object { $_ }

foreach ($svc in $targets) {
  try {
    if ($svc.Status -ne 'Stopped') {
      Write-Info "Stopping service: $($svc.Name) ..."
      Stop-Service -Name $svc.Name -Force -ErrorAction SilentlyContinue
      Start-Sleep -Milliseconds 300
    }
  } catch {}
  try {
    $out = sc.exe delete $svc.Name | Out-String
    if ($LASTEXITCODE -eq 0) { $did.Add("Deleted service: $($svc.Name)") }
  } catch {}
}
# endregion

# region: scheduled tasks
Write-Info "Removing Dropbox scheduled tasks..."
# Known task names
$taskNames = @('\DropboxUpdateTaskMachineCore','\DropboxUpdateTaskMachineUA')

foreach ($tn in $taskNames) {
  try {
    schtasks.exe /Delete /TN $tn /F | Out-Null
    if ($LASTEXITCODE -eq 0) { $did.Add("Deleted scheduled task: $tn") }
  } catch {}
}

# Heuristic: delete any task whose name contains "Dropbox"
# Parse CSV output to safely get paths
$tasksCsv = schtasks.exe /Query /V /FO CSV 2>$null
if ($tasksCsv) {
  $parsed = $tasksCsv | ConvertFrom-Csv
  $dropTasks = $parsed | Where-Object { $_.'TaskName' -match 'Dropbox' }
  foreach ($row in $dropTasks) {
    $name = $row.'TaskName'
    try {
      schtasks.exe /Delete /TN $name /F | Out-Null
      if ($LASTEXITCODE -eq 0) { $did.Add("Deleted scheduled task: $name") }
    } catch {}
  }
}
# endregion

# region: uninstall MSI-registered Dropbox entries
Write-Info "Checking for installed Dropbox entries (MSI/uninstall keys)..."
$uninstallRoots = @(
  'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall',
  'HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall'
)
$toUninstall = @()
foreach ($root in $uninstallRoots) {
  try {
    $toUninstall += Get-ItemProperty "$root\*" | Where-Object {
      $_.DisplayName -and ($_.DisplayName -match 'Dropbox')
    }
  } catch {}
}
$toUninstall = $toUninstall | Sort-Object DisplayName -Unique

if ($toUninstall.Count -gt 0) {
  foreach ($app in $toUninstall) {
    $name = $app.DisplayName
    $uninst = $app.UninstallString
    if (-not $uninst) { continue }

    # Normalize MSI uninstalls to a quiet form
    if ($uninst -match 'MsiExec(\.exe)?\s+/I|/X\s+({[^}]+})') {
      $guid = ($uninst | Select-String -Pattern '{[0-9A-Fa-f-]+' -AllMatches).Matches.Value | Select-Object -First 1
      if ($guid) {
        Write-Info "Uninstalling MSI product $name ($guid) quietly..."
        Start-Process -FilePath "msiexec.exe" -ArgumentList "/x $guid /qn /norestart" -Wait
        if ($LASTEXITCODE -eq 0) { $did.Add("Uninstalled MSI product: $name ($guid)") }
        continue
      }
    }

    # Non-MSI uninstallers: attempt with common silent switches
    Write-Info "Uninstalling non-MSI product $name ..."
    $exe = $uninst
    $args = ""
    if ($uninst.StartsWith('"')) {
      $exe = ($uninst -split '"')[1]
      $args = $uninst.Substring($exe.Length + 2).Trim()
    } else {
      if ($uninst -match '^\S+\s') {
        $exe = $uninst.Split(' ')[0]
        $args = $uninst.Substring($exe.Length).Trim()
      }
    }
    $silentSwitches = @('/quiet','/s','/S','/VERYSILENT','/silent')
    $tried = $false
    foreach ($sw in $silentSwitches) {
      try {
        Start-Process -FilePath $exe -ArgumentList ($args + " " + $sw) -Wait -WindowStyle Hidden
        $did.Add("Attempted uninstall (silent) for: $name")
        $tried = $true
        break
      } catch {}
    }
    if (-not $tried) {
      try {
        Start-Process -FilePath $exe -ArgumentList $args -Wait
        $did.Add("Attempted uninstall (interactive) for: $name")
      } catch {}
    }
  }
} else {
  Write-Info "No uninstall entries with 'Dropbox' found."
}
# endregion

# region: remove stale Event Log source for DbxSvc
Write-Info "Removing stale Event Log source (DbxSvc) if present..."
$evtKey = 'HKLM:\SYSTEM\CurrentControlSet\Services\EventLog\Application\DbxSvc'
if (Test-Path $evtKey) {
  try {
    Remove-Item -LiteralPath $evtKey -Recurse -Force
    $did.Add("Removed Event Log source key: $evtKey")
  } catch {
    Write-Warn "Could not remove Event Log source key (will try to adjust ACL)."
    try {
      $null = takeown.exe /f ($evtKey -replace 'HKLM:\\','HKLM\') /r /d y
      $null = icacls ($evtKey -replace 'HKLM:\\','HKLM\') /grant administrators:F /t
      Remove-Item -LiteralPath $evtKey -Recurse -Force
      $did.Add("Removed Event Log source key after ACL fix: $evtKey")
    } catch {}
  }
} else {
  Write-Info "DbxSvc Event Log source not found (good)."
}
# endregion

# region: delete folders (with ownership fix)
Write-Info "Deleting Dropbox folders..."
$paths = @(
  "C:\ProgramData\Dropbox",
  "C:\ProgramData\DropboxUpdate",
  "C:\Program Files (x86)\Dropbox",
  "$env:LOCALAPPDATA\Dropbox",
  "$env:LOCALAPPDATA\DropboxUpdate",
  "$env:APPDATA\Dropbox"
) | Select-Object -Unique

foreach ($p in $paths) {
  if (Test-Path -LiteralPath $p) {
    try {
      takeown.exe /f "$p" /r /d y | Out-Null
      icacls "$p" /grant administrators:F /t | Out-Null
      Remove-Item -LiteralPath $p -Recurse -Force -ErrorAction SilentlyContinue
      if (-not (Test-Path -LiteralPath $p)) { $did.Add("Deleted folder: $p") }
    } catch {
      Write-Warn "Failed to delete $p. It may be in use."
    }
  }
}
# endregion

# region: optional perf counter tidy (no-op if you don't want it)
$rebuildPerf = $false  # set $true if you want to rebuild counters
if ($rebuildPerf) {
  Write-Info "Rebuilding perf counters (optional step)..."
  try { lodctr /r | Out-Null; winmgmt /resyncperf | Out-Null; $did.Add("Rebuilt perf counters") } catch {}
}
# endregion

# region: summary
Write-Host ""
Write-OK "Cleanup complete."
if ($did.Count -gt 0) {
  Write-Host "Actions taken:" -ForegroundColor Green
  $did | Sort-Object | Get-Unique | ForEach-Object { "  - $_" } | Write-Host
} else {
  Write-Host "No Dropbox remnants were found to remove." -ForegroundColor Green
}

Write-Host ""
Write-Info "Recommended next steps:"
Write-Host "  1) Reboot your PC." -ForegroundColor Cyan
Write-Host "  2) Install Dropbox using the OFFLINE installer (Run as Administrator)." -ForegroundColor Cyan
Write-Host "     URL: https://www.dropbox.com/download?full=1" -ForegroundColor Cyan
# endregion