diff --git a/hledger-lib/Hledger/Data/Timeclock.hs b/hledger-lib/Hledger/Data/Timeclock.hs
index 9507408de..e4a356dda 100644
--- a/hledger-lib/Hledger/Data/Timeclock.hs
+++ b/hledger-lib/Hledger/Data/Timeclock.hs
@@ -106,21 +106,28 @@ pairClockEntries (entry : rest) actives sessions
     (idate, odate) = (localDay itime, localDay otime)
     omidnight = entry {tldatetime = itime {localDay = idate, localTimeOfDay = TimeOfDay 23 59 59}}
     imidnight = inentry {tldatetime = itime {localDay = addDays 1 idate, localTimeOfDay = midnight}}
-    (sessions', actives', rest') =
-      if odate > idate
-      then (Session {in' = inentry, out = omidnight} : sessions, imidnight : newactive, entry : rest)
-      else (Session {in' = inentry, out = entry} : sessions, newactive, rest)
-    l = show $ unPos $ sourceLine $ tlsourcepos entry
-    c = unPos $ sourceColumn $ tlsourcepos entry
-    inentries =
-      if any (\e -> tlaccount e == tlaccount entry) actives
-      then error' $ printf
-        "%s:\n%s\n%s\n\nEncountered clockin entry for session \"%s\" that is already active."
-        (sourcePosPretty $ tlsourcepos entry)
-        (l ++ " | " ++ show entry)
-        (replicate (length l) ' ' ++ " |" ++ replicate c ' ' ++ "^")
-        (tlaccount entry)
-      else entry : actives
+    (sessions', actives', rest')
+      | odate > idate = (Session {in' = inentry, out = omidnight} : sessions, imidnight : newactive, entry : rest)
+      | otherwise     = (Session {in' = inentry, out = entry} : sessions, newactive, rest)
+    inentries = case filter ((== tlaccount entry) . tlaccount) actives of
+      []                -> entry : actives
+      activesinthisacct -> error' $ T.unpack $ makeTimeClockErrorExcerpt entry $ T.unlines $ [
+         "Simultaneous sessions with the same account name are not supported."
+        ,"This clockin overlaps with:"
+        ] <> map (flip makeTimeClockErrorExcerpt "") activesinthisacct
+        -- XXX better to show full session(s)
+        -- <> map T.show (filter ((`elem` activesinthisacct).in') sessions)
+
+makeTimeClockErrorExcerpt :: TimeclockEntry -> T.Text -> T.Text
+makeTimeClockErrorExcerpt e@TimeclockEntry{tlsourcepos=pos} msg = T.unlines [
+   T.pack (sourcePosPretty pos) <> ":"
+  ,l <> " | " <> T.show e
+  -- ,T.replicate (T.length l) " " <> " |" -- <> T.replicate c " " <> "^")
+  ,""
+  ] <> msg
+  where
+    l = T.show $ unPos $ sourceLine $ tlsourcepos e
+    -- c = unPos $ sourceColumn $ tlsourcepos e
 
 -- | Convert time log entries to journal transactions, allowing multiple clocked-in sessions at once.
 -- This is the new, default behaviour.
diff --git a/hledger/hledger.m4.md b/hledger/hledger.m4.md
index 6e71502d7..b911193a7 100644
--- a/hledger/hledger.m4.md
+++ b/hledger/hledger.m4.md
@@ -4804,6 +4804,9 @@ $ hledger -f t.timeclock print
 
 ```
 
+Note, you can have overlapping sessions (multiple sessions open simultaneously), but they must have different account names.
+Overlapping sessions with the same account name are currently not supported currently.
+
 Here is a
 [sample.timeclock](https://raw.github.com/simonmichael/hledger/master/examples/sample.timeclock) to
 download and some queries to try:
diff --git a/hledger/test/errors/tcorderedactions.test b/hledger/test/errors/tcorderedactions.test
index b6d768539..e79648341 100644
--- a/hledger/test/errors/tcorderedactions.test
+++ b/hledger/test/errors/tcorderedactions.test
@@ -1,9 +1,9 @@
 $$$ hledger check -f  tcorderedactions.timeclock
 >>>2 /Error: .*tcorderedactions.timeclock:8:1:
 8 \| i 2022-01-01 00:01:00 a  
-  \| \^
 
-Encountered clockin entry for session "a" that is already active.
+Simultaneous sessions with the same account name are not supported.
+This clockin overlaps with:
 /
 >>>= 1
 
diff --git a/hledger/test/timeclock.test b/hledger/test/timeclock.test
index a65fbfc41..7a872eb8d 100644
--- a/hledger/test/timeclock.test
+++ b/hledger/test/timeclock.test
@@ -192,6 +192,17 @@ $ hledger -f timeclock:- print
 
 >=
 
+# ** 14. Sessions with the same account name may not overlap (#2417).
+<
+i 2024-01-01 13:00:00 a
+o 2024-01-01 15:00:00
+i 2024-01-01 14:00:00 a
+o 2024-01-01 15:00:00
+
+$ hledger -f timeclock:- print
+>2 /Simultaneous sessions with the same account name are not supported./
+>=!0
+
 # ** OLD:
 
 ## multi-day sessions get a new transaction for each day