For completeness, confirming my smartcard works without issue in all aspects of GnuPG.

Ensured GpgWin\bin and GpgWin\bin_64 were both in the path...

Confirmed the same error messages and stack traces.

PS C:\Program Files (x86)> $env:PATH -split ';' | select-string gpg

C:\Program Files (x86)\Gpg4win\bin_64 C:\Program Files (x86)\Gpg4win\bin C:\Program Files (x86)\Gpg4win\..\GnuPG\bin

PS C:\Program Files (x86)> $env:PATH -split ';' | select-string gpg | foreach { ls $_ }

   Directory: C:\Program Files (x86)\Gpg4win\bin_64

Mode LastWriteTime Length Name

-a--- 3/11/2024 6:22 AM 504304 gpgex.dll -a--- 3/11/2024 6:22 AM 128496 gpgme-json.exe -a--- 3/11/2024 6:22 AM 65024 gpgme-w32spawn.exe -a--- 3/11/2024 6:22 AM 2900976 gpgol.dll -a--- 3/11/2024 6:22 AM 158192 libassuan-0.dll -a--- 3/11/2024 6:22 AM 252912 libgpg-error-0.dll -a--- 3/11/2024 6:22 AM 420848 libgpgme-11.dll -a--- 3/11/2024 6:22 AM 418800 libgpgmepp-6.dll -a--- 3/11/2024 6:23 AM 66544 libwinpthread-1.dll

   Directory: C:\Program Files (x86)\Gpg4win\bin

Mode LastWriteTime Length Name

d---- 8/31/2024 7:21 PM data d---- 8/31/2024 7:21 PM iconengines d---- 8/31/2024 7:21 PM imageformats d---- 8/31/2024 7:21 PM platforms d---- 8/31/2024 7:21 PM plugins d---- 8/31/2024 7:21 PM printsupport d---- 8/31/2024 7:21 PM styles d---- 8/31/2024 7:21 PM translations -a--- 3/11/2024 6:17 AM 73216 gpg-error.exe -a--- 3/11/2024 6:17 AM 548864 gpgex.dll -a--- 8/31/2024 7:21 PM 242 gpgme-chrome.json -a--- 8/31/2024 7:21 PM 242 gpgme-edge.json -a--- 3/11/2024 6:17 AM 121344 gpgme-json.exe -a--- 8/31/2024 7:21 PM 221 gpgme-mozilla.json -a--- 3/11/2024 6:22 AM 65024 gpgme-w32spawn.exe -a--- 3/11/2024 6:18 AM 3059200 gpgol.dll -a--- 3/11/2024 6:17 AM 304128 gpgolconfig.exe -a--- 3/11/2024 6:18 AM 252928 gpgolkeyadder.exe -a--- 3/11/2024 6:18 AM 1018880 iconv.dll -a--- 3/11/2024 6:18 AM 116736 intl.dll -a--- 3/11/2024 6:18 AM 4981760 kleopatra.exe -a--- 3/11/2024 6:18 AM 153088 libassuan-0.dll -a--- 3/11/2024 6:18 AM 856576 libfreetype.dll -a--- 3/11/2024 6:22 AM 132096 libgcc_s_dw2-1.dll -a--- 3/11/2024 5:50 AM 0 libgcc_s_sjlj-1.dll -a--- 3/11/2024 6:18 AM 241664 libgpg-error-0.dll -a--- 3/11/2024 6:18 AM 404480 libgpgme-11.dll -a--- 3/11/2024 6:18 AM 429568 libgpgmepp-6.dll -a--- 3/11/2024 6:18 AM 513024 libical.dll -a--- 3/11/2024 6:18 AM 116224 libicalss.dll -a--- 3/11/2024 6:18 AM 114688 libicalvcal.dll -a--- 3/11/2024 6:18 AM 1018880 libiconv-2.dll -a--- 3/11/2024 6:18 AM 116736 libintl-8.dll -a--- 3/11/2024 6:18 AM 339456 libjpeg-9.dll -a--- 3/11/2024 6:18 AM 289280 libKF5Archive.dll -a--- 3/11/2024 6:18 AM 335360 libKF5Bookmarks.dll -a--- 3/11/2024 6:18 AM 1041408 libKF5CalendarCore.dll -a--- 3/11/2024 6:19 AM 281088 libKF5Codecs.dll -a--- 3/11/2024 6:19 AM 278528 libKF5Completion.dll -a--- 3/11/2024 6:19 AM 510976 libKF5ConfigCore.dll -a--- 3/11/2024 6:19 AM 172032 libKF5ConfigGui.dll -a--- 3/11/2024 6:19 AM 463360 libKF5ConfigWidgets.dll -a--- 3/11/2024 6:19 AM 788992 libKF5CoreAddons.dll -a--- 3/11/2024 6:19 AM 72192 libKF5Crash.dll -a--- 3/11/2024 6:19 AM 195072 libKF5GuiAddons.dll -a--- 3/11/2024 6:19 AM 389120 libKF5I18n.dll -a--- 3/11/2024 6:19 AM 313360 libKF5IconThemes.dll -a--- 3/11/2024 6:19 AM 356864 libKF5ItemModels.dll -a--- 3/11/2024 6:19 AM 258048 libKF5ItemViews.dll -a--- 3/11/2024 6:19 AM 134656 libKF5JobWidgets.dll -a--- 3/11/2024 6:19 AM 1828864 libKF5KIOCore.dll -a--- 3/11/2024 6:19 AM 206336 libKF5KIOGui.dll -a--- 3/11/2024 6:19 AM 700416 libKF5KIOWidgets.dll -a--- 3/11/2024 6:19 AM 439296 libKF5Parts.dll -a--- 3/11/2024 6:19 AM 797184 libKF5Service.dll -a--- 3/11/2024 6:20 AM 804864 libKF5Solid.dll -a--- 3/11/2024 6:20 AM 235008 libKF5SonnetCore.dll -a--- 3/11/2024 6:20 AM 217088 libKF5SonnetUi.dll -a--- 3/11/2024 6:20 AM 302080 libKF5TextWidgets.dll -a--- 3/11/2024 6:20 AM 180736 libKF5ThreadWeaver.dll -a--- 3/11/2024 6:20 AM 1527808 libKF5WidgetsAddons.dll -a--- 3/11/2024 6:20 AM 208896 libKF5WindowSystem.dll -a--- 3/11/2024 6:20 AM 1053696 libKF5XmlGui.dll -a--- 3/11/2024 6:20 AM 103936 libkleopatraclientcore.dll -a--- 3/11/2024 6:20 AM 45568 libkleopatraclientgui.dll -a--- 3/11/2024 6:20 AM 1613312 libKPim5Libkleo.dll -a--- 3/11/2024 6:20 AM 73728 libKPim5Mbox.dll -a--- 3/11/2024 6:20 AM 365056 libKPim5Mime.dll -a--- 3/11/2024 6:20 AM 350208 libKPim5MimeTreeParserCore.dll -a--- 3/11/2024 6:20 AM 142848 libKPim5MimeTreeParserWidgets.dll -a--- 3/11/2024 6:20 AM 1165824 libOkular5Core.dll -a--- 3/11/2024 6:20 AM 449024 libopenjp2.dll -a--- 3/11/2024 6:21 AM 376832 libpcre2-16.dll -a--- 3/11/2024 6:21 AM 273920 libpng16-16.dll -a--- 3/11/2024 6:21 AM 3136512 libpoppler-130.dll -a--- 3/11/2024 6:21 AM 518656 libpoppler-qt5-1.dll -a--- 3/11/2024 6:21 AM 1432064 libqgpgme-15.dll -a--- 3/11/2024 6:23 AM 1848832 libstdc++-6.dll -a--- 3/11/2024 6:21 AM 571392 libtiff.dll -a--- 3/11/2024 6:23 AM 62448 libwinpthread-1.dll -a--- 3/11/2024 6:17 AM 45582 md5sum.exe -a--- 3/11/2024 6:21 AM 294400 okular.exe -a--- 3/11/2024 6:21 AM 189440 overlayer.exe -a--- 3/11/2024 6:21 AM 107520 paperkey.exe -a--- 3/11/2024 6:21 AM 111104 pinentry-w32.exe -a--- 3/11/2024 6:21 AM 175104 pinentry.exe -a--- 8/31/2024 7:21 PM 101 qt.conf -a--- 3/11/2024 6:21 AM 6471664 Qt5Core.dll -a--- 3/11/2024 6:21 AM 7576048 Qt5Gui.dll -a--- 3/11/2024 6:21 AM 1414128 Qt5Network.dll -a--- 3/11/2024 6:21 AM 353776 Qt5PrintSupport.dll -a--- 3/11/2024 6:21 AM 352240 Qt5Svg.dll -a--- 3/11/2024 6:21 AM 6725104 Qt5Widgets.dll -a--- 3/11/2024 6:21 AM 258544 Qt5WinExtras.dll -a--- 3/11/2024 6:22 AM 260592 Qt5Xml.dll -a--- 3/11/2024 6:22 AM 236544 resolver.exe -a--- 3/11/2024 6:22 AM 358400 scute.dll -a--- 3/11/2024 6:23 AM 60416 sha1sum.exe -a--- 3/11/2024 6:23 AM 56320 sha256sum.exe -a--- 3/11/2024 6:22 AM 143360 zlib1.dll

   Directory: C:\Program Files (x86)\gnupg\bin

Mode LastWriteTime Length Name

-a--- 3/7/2024 5:57 AM 147968 dirmngr_ldap.exe -a--- 3/7/2024 5:57 AM 807936 dirmngr.exe -a--- 3/7/2024 5:57 AM 482816 gpg-agent.exe -a--- 3/7/2024 5:58 AM 346624 gpg-card.exe -a--- 3/7/2024 5:57 AM 154112 gpg-check-pattern.exe -a--- 3/7/2024 5:57 AM 187392 gpg-connect-agent.exe -a--- 10/6/2023 4:45 AM 1815 gpg-disable-keyboxd.bat -a--- 10/6/2023 4:45 AM 2027 gpg-enable-keyboxd.bat -a--- 3/7/2024 5:57 AM 117248 gpg-preset-passphrase.exe -a--- 3/7/2024 5:57 AM 273920 gpg-wks-client.exe -a--- 3/7/2024 5:57 AM 1346048 gpg.exe -a--- 3/7/2024 5:58 AM 209920 gpgconf.exe -a--- 3/7/2024 5:58 AM 65024 gpgme-w32spawn.exe -a--- 3/7/2024 5:58 AM 682496 gpgsm.exe -a--- 3/7/2024 5:58 AM 188928 gpgtar.exe -a--- 3/7/2024 5:58 AM 685056 gpgv.exe -a--- 3/7/2024 5:58 AM 350208 keyboxd.exe -a--- 3/7/2024 5:58 AM 157960 libassuan-0.dll -a--- 3/7/2024 5:58 AM 1339888 libgcrypt-20.dll -a--- 3/7/2024 5:58 AM 252808 libgpg-error-0.dll -a--- 3/7/2024 5:58 AM 413608 libgpgme-11.dll -a--- 3/7/2024 5:58 AM 304856 libksba-8.dll -a--- 3/7/2024 5:58 AM 41520 libnpth-0.dll -a--- 3/7/2024 5:58 AM 1210072 libsqlite3-0.dll -a--- 3/7/2024 5:58 AM 111104 pinentry-basic.exe -a--- 3/7/2024 5:58 AM 650752 scdaemon.exe -a--- 3/7/2024 5:58 AM 144384 zlib1.dll

PS C:\Program Files (x86)>

Tried using only the 16-character sub key id for the [S][C] sub key.

Screenshot attached.

Set GPGME_DEBUG in environment and confirmed presence in Thunderbird process. [See screenshot]

No GPGME debug log created.

PS C:\Users\||redacted||\AppData\Local\Temp> ls gpg* PS C:\Users\||redacted||\AppData\Local\Temp>

Moved GpgWin\bin and GpgWin\bin_64 to the beginning of the path to ensure they were present in the env o the running process.

Ugh. No idea how but everything is working. Now there is nothing in the logs about errors; the "GPGME isn't working" does not appear anymore.

My private key has a number UIDs although originally, I couldn't even sign or decrypt with the primary UID, nor with any of the sub UIDs.

I had originally added identities for the sub UIDs under the corresponding accounts where those UIDs can be sent/received. Eventually I discovered that each identity has its own e2ee tab, and specified the same private key ID for each of the identities. Still unsure how that would make signing and decrypt work for the primary UID when it wouldn't before.

Perhaps post in the encryption list. https://thunderbird.topicbox.com/groups/e2ee