diff --git a/ChangeLog b/ChangeLog
index 154d1d3..6ad958c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2022-02-28 Richard Frith-Macdonald <rfm@gnu.org>
+
+	* EcCommand.m:
+	When building config for a process, only count the part of a process
+	name after the last hyphen as an instance ID if it is entirely
+	composed of digits.
+
 2022-02-08 Richard Frith-Macdonald <rfm@gnu.org>
 
 	* EcCommand.m:
diff --git a/EcCommand.m b/EcCommand.m
index 5c61c4e..37e0695 100644
--- a/EcCommand.m
+++ b/EcCommand.m
@@ -4954,7 +4954,25 @@ NSLog(@"Problem %@", localException);
 		  options: NSBackwardsSearch | NSLiteralSearch];
   if (r.length > 0)
     {
+      NSString		*inst = [name substringFromIndex: NSMaxRange(r)];
+      NSUInteger	len = [inst length];
+
       base = [name substringToIndex: r.location];
+      if ([inst length] == 0)
+	{
+	  base = nil;		// Not an instance ID after hyphen
+	}
+      else
+        {
+	  while (len-- > 0)
+	    {
+	      if (!isdigit([inst characterAtIndex: len]))
+		{
+		  base = nil;	// not positive integer after hyphen
+		  break;
+		}
+	    }
+        }
     }
   else
     {