TB 137.0.1 (64-bit)
Edition Windows 11 Pro
Version 24H2
OS build 26100.3775
Experience Windows Feature Experience Pack 1000.26100.66.0
Was repeatedly encountering "Canno… (read more)
TB 137.0.1 (64-bit)
Edition Windows 11 Pro
Version 24H2
OS build 26100.3775
Experience Windows Feature Experience Pack 1000.26100.66.0
Was repeatedly encountering "Cannot read summary file" when opening TB. Some research indicated this issue goes back many years and can be intermittent. After much "repair folder" the issues seems to have abated. However, as part of my research I explored the user-local filesystem tree for TB for one of the larger email accounts I monitor, as in
C:\Users\user_name\AppData\Roaming\Thunderbird\Profiles\<8_chars_profile_id>.default\ImapMail\<mail_server_name>\email_top_level_folder_names_as_NTFS_directory_names.
From this I discovered that with a Message Store Type of File-per-folder, TB constructs a filesystem directory tree that replicates the email folder tree, including the naming, presented by the IMAP email server. Not an unreasonable design choice but one with a potential flaw. Given that a Windows user_name can be 20 characters, an FQDN hostname can be 253 characters, and the max IMAP folder name length can be uncertain but apparently good practice is no more than 250 characters,...
- What happens when TB goes to create a deep-in-tree directory having a pathname that exceeds the Windows maximum of 260 bytes?
- Suppose this deep-in-tree directory is not originated from the TB UI but rather from a TB update scan of an IMAP server?
The user could have created IMAP folders via a Web interface with longish names in a 3 or 4 deep hierarchy not understanding the total pathname length limit in how TB echos the IMAP folder tree with a directory tree. The user then points TB at this email account and oops. Does TB fall over?
The default leading part of the TB AppData pathname above could be 93 characters alone before we get to the email server FQDN. Windows 11 Pro does offer a Group Policy setting to enable long pathnames up to 32k for manifested apps but this policy is not configured OOB.
Regards.