PuTTY bug win-jumplist-trouble
summary: Trouble with Windows 'jump lists' of recently used sessions since 0.68
class: bug: This is clearly an actual problem we want fixed.
difficulty: taxing: Needs external things we don't have (standards, users etc)
priority: high: This should be fixed in the next release.
Various people have reported that the Windows 'jump list' features,
which maintain a list of recently used sessions (and optionally
'pinned' sessions) accessible via the taskbar button and/or Start
Menu, have been broken in various ways since the 0.68 release.
There's a fair amount of evidence that this was triggered by our fix for
This fix involved changing how PuTTY identifies itself to Windows for
the purposes of storing recent session information (using
SetCurrentProcessExplicitAppUserModelID() where previously we
were doing nothing). That fix didn't make any provision for migrating
any existing stored information; in our pre-release testing, we saw
some transitory anomalies from this, but it seemed to work itself out
without forgetting recently used sessions, suggesting that Windows can
somehow manage the migration itself at least under some circumstances.
However, others have seen more permanent effects.
We suspect the exact symptoms seen may depend on the exact history of
which versions of PuTTY were run when by what exact means, and/or
which flavour of installers were installed/uninstalled/upgraded in
what order. Which makes investigating this systematically rather
If anyone has deep knowledge of how Windows jump list storage works
(particularly with respect to how applications are identified) and can
suggest ways to mitigate this in future releases without making things
worse, that would be helpful.
- The PuTTY shortcut on the Start Menu, which normally has a
right-arrow leading to a list of recent and optionally pinned
sessions, does not do so.
- This at least we have some sort of explanation for; we should have
made the PuTTY shortcuts created by the installer reference the same
AppUserModelID as the PuTTY executable sets at runtime. We have
rectified this in the post-0.68 snapshot installers
- However, in a test on Windows 7, we found that the shortcut did
get its list of saved sessions back after a while with no such care
taken. Not sure how that happened; I suppose I did launch PuTTY from
the Start Menu at some point in the proceedings, so maybe Windows went
"aha, this shortcut launches an executable with this AppUserModelID, I
shall remember that for next time".
- One user suggests that the problem only happens if you uninstall
0.67 and then install 0.68 (with any installer); if you upgrade from
the 0.67 to the 0.68 exe uninstaller without uninstalling, the issue
is not seen.
- Ending up with two PuTTY icons on the taskbar; one permanent
'pinned' icon, and one for the running session. The 'pinned' icon,
which would normally have a list of recent or pinned sessions, does
not, so is not very useful.
- But others report that while you can end up with two different
icons, they behave sensibly.
- Recent sessions appear, but the 'pin' icon doesn't do anything
(demo video). Windows 10,
- Another user hints that this kind of brokenness (and also broken
'Remove from this list' functionality) might be correlated with the
Windows version: broken on 'Windows 10 1607 (Redstone 1 / Anniversary
Update)', not broken on Windows 7/8.1/'Windows 10 1511 (Threshold 2)',
and affecting both 0.67 and 0.68, although it's not clear what the
installation history was so maybe merely having had a new version
installed at some point causes permanent confusion.
- PuTTY's taskbar icon is a generic blank-page sort of icon rather
than the usual blue-and-yellow PuTTY icon. Has no "Pin this program
to the taskbar" option. Other options ("Run Pageant", recent sessions)
are present and work. PuTTY icon appears in Alt-Tab. (Observed on
Windows 7 with 0.71.)
- Cosmetic: the way PuTTY identifies itself on the taskbar menu item
that launches the executable without arguments seems to randomly
fluctuate between 'PuTTY' and 'SSH, Telnet and Rlogin client' (the
FileDescription in the resources). This doesn't obviously hurt
anything, but may be a clue.
Anyone investigating or suffering from this may be interested to know
option requests Windows to delete its stored information about
recent/pinned sessions. We make no attempt to account for different
versions of PuTTY's information being stored in different places; so
running this command with PuTTY 0.67 or earlier presumably deletes
pre-ExplicitAppUserModelID information, and running it with PuTTY 0.68
or later deletes information identified the new way. Note that this
option also deletes all your saved sessions and host keys;
while you can be more selective by saving and restoring
HKEY_CURRENT_USER\Software\SimonTatham\PuTTY using REGEDIT,
you probably shouldn't try this unless you're confident, or don't mind
losing this information. (People investigating the registry should
note that the Jumplist key in this registry location is
not the storage under discussion here; it is a separate
record that PuTTY maintains because the Windows storage is write-only,
and hasn't moved between versions. The storage affected by
ExplicitAppUserModelID is maintained elsewhere by Windows and we don't
know where it is.)
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