Sample data and admin not showing in magento 2

As I noticed we are having some issue in Magento 2 with windows operating system, where it was not able to fetch the directory path correctly. For that, need to apply some core fix. try with below solution it might help you.

Navigate to below file

vendormagentoframeworkViewElementTemplateFileValidator.php

In function, isPathInDirectories added below line

$realPath = str_replace(”, ‘/’, $realPath);

or refer below code function

protected function isPathInDirectories($path, $directories)
{
    if (!is_array($directories)) {
        $directories = (array)$directories;
    }
    $realPath = $this->fileDriver->getRealPath($path);
    $realPath = str_replace('\', '/', $realPath); // extra code added
    foreach ($directories as $directory) {
        if (0 === strpos($realPath, $directory)) {
            return true;
        }
    }
    return false;
}