Issue #1194 Check machine instance directory on start

Validate that required SSH key files exist in ~/.crc/machines/crc/
before attempting to start an existing VM. Missing files now produce
a clear error message instead of confusing SSH connection failures.

Resolves #1194

Author: sebrandon1

pkg/crc/machine/start.go

@@ -282,6 +282,12 @@ func (client *client) Start(ctx context.Context, startConfig types.StartConfig)
 		return nil, errors.Wrap(err, "Cannot determine if VM exists")
 	}
 
+	if exists {
+		if err := checkMachineInstanceDir(); err != nil {
+			return nil, err
+		}
+	}
+
 	bundleNameFromURI, err := bundle.GetBundleNameFromURI(startConfig.BundlePath)
 	if err != nil {
 		return nil, errors.Wrap(err, "Error getting bundle name")
@@ -891,6 +897,19 @@ func startMicroshift(ctx context.Context, sshRunner *crcssh.Runner, ocConfig oc.
 	return cluster.WaitForAPIServer(ctx, ocConfig)
 }
 
+func checkMachineInstanceDir() error {
+	requiredFiles := []string{
+		constants.GetPrivateKeyPath(),
+		constants.GetPublicKeyPath(),
+	}
+	for _, filePath := range requiredFiles {
+		if !crcos.FileExists(filePath) {
+			return fmt.Errorf("Required file %s is missing from the instance directory. Please delete the instance with 'crc delete' and recreate it with 'crc start'", filePath)
+		}
+	}
+	return nil
+}
+
 func ensurePullSecretPresentInVM(sshRunner *crcssh.Runner, pullSec cluster.PullSecretLoader) error {
 	if pullSecret, _, err := sshRunner.RunPrivate("sudo", "cat", "/etc/crio/openshift-pull-secret"); err == nil {
 		if err := validation.ImagePullSecret(pullSecret); err == nil {