diff --git a/doGui.go b/doGui.go
index 9a902ee..8263587 100644
--- a/doGui.go
+++ b/doGui.go
@@ -6,7 +6,6 @@ package main
 // An app to submit patches for the 30 GO GUI repos
 
 import (
-	"fmt"
 	"os"
 	"strings"
 	"time"
@@ -21,7 +20,7 @@ import (
 func debug() {
 	for {
 		time.Sleep(10 * time.Second)
-		log.Info("TODO: use this debug loop for something?")
+		// log.Info("TODO: use this debug loop for something?")
 	}
 }
 
@@ -40,17 +39,48 @@ func addDrive(devname string, displayDesc string) *Block {
 }
 
 func switchDrive(blk *Block) {
+	var inUse bool = false
 	me.currentDev = blk
-	me.parted.SetText("Partition " + blk.Name)
+
+	if isBlockDeviceInUse(blk.Name) {
+		log.Info("Is in use?", blk.Name)
+		me.parted.SetText("Partition " + blk.Name + " (in use)")
+		me.parted.Disable()
+		inUse = true
+	} else {
+		log.Info("Is probably not in use?", blk.Name)
+		me.parted.SetText("Partition " + blk.Name + " as gpt boot disk")
+		me.parted.Enable()
+	}
 
 	log.Info("check if", me.currentDev.Name, "is in use")
 	result, err := shell.RunVerbose([]string{"parted", me.currentDev.Name, "print"})
 	log.Info("result =", result.Stdout, "err =", err)
 	out := strings.Join(result.Stdout, "\n")
 	if err != nil {
-		out += fmt.Sprintf("err = %v", err)
+		out += log.Sprintf("err = %v", err)
 	}
 	me.driveInfoBox.SetText(out)
+
+	if inUse {
+		// if the drive is in use already, you can just stop here
+		return
+	}
+
+	if ok, err := hasPartitionTable(blk.Name); err != nil {
+		out := log.Sprintf("Error checking partition table: %s\n", err)
+		log.Warn(out)
+		me.parted.Disable()
+		me.driveInfoBox.SetText(out)
+	} else {
+		if !ok {
+			log.Printf("%s has no partition table safe for gdisk\n", blk.Name)
+		} else {
+			log.Printf("%s already has a partition table\n", blk.Name)
+			me.parted.SetText("Partition " + blk.Name + " (has partitions)")
+			me.parted.Disable()
+		}
+	}
 }
 
 func doGui() {
@@ -95,7 +125,7 @@ func drawWindow(win *gadgets.GenericWindow) {
 			log.Info("You must select a drive first")
 			return
 		}
-		log.Info("TODO: figure out if the drive is in use")
+		log.Info("If you got here, gdisk should be safe to run on", me.currentDev.Name)
 	})
 
 	grid.NextRow()
diff --git a/hasPartitionTable.go b/hasPartitionTable.go
new file mode 100644
index 0000000..96ed786
--- /dev/null
+++ b/hasPartitionTable.go
@@ -0,0 +1,34 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+// HasPartitionTable runs `parted <device> print` and returns:
+// - true if the disk has a recognized partition table
+// - false if it's unrecognized or empty
+func hasPartitionTable(dev string) (bool, error) {
+	cmd := exec.Command("parted", "-s", dev, "print")
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+
+	err := cmd.Run()
+	output := out.String()
+
+	// Check for known "no label" pattern
+	if strings.Contains(output, "unrecognised disk label") ||
+		strings.Contains(output, "unrecognized disk label") ||
+		strings.Contains(output, "Error") {
+		return false, nil
+	}
+
+	if err != nil {
+		return false, fmt.Errorf("parted failed: %w: %s", err, output)
+	}
+
+	return true, nil
+}
diff --git a/isDriveInUse.go b/isDriveInUse.go
new file mode 100644
index 0000000..912ae07
--- /dev/null
+++ b/isDriveInUse.go
@@ -0,0 +1,95 @@
+package main
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"go.wit.com/log"
+)
+
+func isBlockDeviceInUse(dev string) bool {
+	base := filepath.Base(dev)
+
+	// 1. Check /proc/mounts
+	if isMounted(dev, base) {
+		log.Info(dev, "dev is mounted (/proc/mounts)")
+		return true
+	}
+
+	// 2. Check /proc/swaps
+	if isSwap(dev) {
+		log.Info(dev, "dev is used by swap (/proc/swaps)")
+		return true
+	}
+
+	// 3. Check /proc/mdstat for RAID
+	if isInRAID(base) {
+		log.Info(dev, "dev is in software raid (/proc/mdstat)")
+		return true
+	}
+
+	// 4. Check sysfs for device-mapper or LVM use
+	if hasDMHolders(base) {
+		log.Info(dev, "dev has lvm partitions")
+		return true
+	}
+
+	log.Info(dev, "dev appears to be unused")
+	return false
+}
+
+func isMounted(dev, base string) bool {
+	f, err := os.Open("/proc/mounts")
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		if strings.HasPrefix(scanner.Text(), dev) || strings.Contains(scanner.Text(), base) {
+			return true
+		}
+	}
+	return false
+}
+
+func isSwap(dev string) bool {
+	f, err := os.Open("/proc/swaps")
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		if strings.HasPrefix(scanner.Text(), dev) {
+			return true
+		}
+	}
+	return false
+}
+
+func isInRAID(base string) bool {
+	f, err := os.Open("/proc/mdstat")
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		if strings.Contains(scanner.Text(), base) {
+			return true
+		}
+	}
+	return false
+}
+
+func hasDMHolders(base string) bool {
+	path := filepath.Join("/sys/block", base, "holders")
+	entries, err := os.ReadDir(path)
+	return err == nil && len(entries) > 0
+}