diff --git a/PVE/CLI/pve8to9.pm b/PVE/CLI/pve8to9.pm
index 7305a7b..b147f56 100644
--- a/PVE/CLI/pve8to9.pm
+++ b/PVE/CLI/pve8to9.pm
@@ -27,6 +27,7 @@ use PVE::Storage::Plugin;
 use PVE::Tools qw(run_command split_list file_get_contents trim);
 use PVE::QemuConfig;
 use PVE::QemuServer;
+use PVE::QemuServer::Drive;
 use PVE::QemuServer::Machine;
 use PVE::QemuServer::Network;
 use PVE::VZDump::Common;
@@ -1076,6 +1077,51 @@ my sub check_qemu_machine_versions {
     }
 }
 
+sub check_qemu_tpmstate_volumes {
+    log_info("Checking VM TPM state volumes for qcow2 files containing raw data..");
+
+    my $storecfg = PVE::Storage::config();
+    my $affected = [];
+
+    my $vms = PVE::QemuServer::config_list();
+    for my $vmid (sort { $a <=> $b } keys $vms->%*) {
+        my $conf = PVE::QemuConfig->load_config($vmid);
+        next if !$conf->{tpmstate0};
+
+        my $volid = PVE::QemuServer::Drive::parse_drive('tpmstate0', $conf->{tpmstate0})->{file};
+        eval {
+            my ($storeid) = PVE::Storage::parse_volume_id($volid);
+            my $format = (PVE::Storage::parse_volname($storecfg, $volid))[6];
+            my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
+            # only volumes on file based storages could end up like this
+            return if $format ne 'qcow2' || !$scfg->{path};
+
+            my $path = PVE::Storage::path($storecfg, $volid);
+            open(my $fh, '<', $path) or die "unable to open '$path' - $!\n";
+            my $magic = '';
+            read($fh, $magic, 4);
+            close($fh);
+
+            # before qemu-server 8.3.3, swtpm_setup used the qcow2 overlay of linked clones as raw
+            # file and overwrote it with a new state
+            push $affected->@*, "VM $vmid: $volid" if $magic ne "QFI\xfb";
+        };
+        log_skip("could not check TPM state volume '$volid' of VM $vmid - $@") if $@;
+    }
+
+    if (!scalar($affected->@*)) {
+        log_pass("No qcow2 TPM state volumes with raw data found.");
+        return;
+    }
+
+    log_warn(
+        "The TPM state volumes of the following VMs are qcow2 files that contain raw data, which"
+            . " happened with linked clones. Such a VM fails to start in Proxmox VE 9. Rename the"
+            . " file to end with '.raw' and adapt the 'tpmstate0' line of the VM config accordingly,"
+            . " also dropping the base volume, like '101/base-101-disk-2.raw/':\n\t"
+            . join("\n\t", $affected->@*));
+}
+
 my sub check_max_length {
     my ($raw, $max_length, $warning) = @_;
     log_warn($warning) if defined($raw) && length($raw) > $max_length;
@@ -2098,6 +2144,8 @@ sub check_virtual_guests {
     }
 
     check_qemu_machine_versions();
+
+    check_qemu_tpmstate_volumes();
 }
 
 my $LEGACY_IPAM_DB = "/etc/pve/priv/ipam.db";