Windows 11 June 2026 update, which was supposed to make PCs faster, is crashing some PCs with BSODs, breaking OneDrive integration in File Explorer and custom folder icons, and causing other problems. We're seeing reports that Windows 11 KB5094126 is causing boot failures on some PCs, mostly HP enterprise hardware. The worst reports involve BitLocker recovery loops, Black Screen of Death/BSOD failures, Secure Boot signature errors, and error 0xc0430001. Affected models appear to include HP EliteBook 840 G10, HP ProBook 460 G11, HP Engage One Pro G2 AiO POS, HP ZBook, and some Dell Precision systems. The likely trigger is Secure Boot certificate handling + EFI partition space. On older images with a 100MB EFI partition, Windows may fail to update Boot Manager because there isn’t enough space, especially on HP systems where firmware recovery files can bloat EFI. There are also File Explorer cloud integration issues. OneDrive, and in some cases Dropbox or iCloud Drive, may stop opening from the sidebar/tray shortcut after KB5094126. Microsoft also confirms desktop.ini hardening can break custom folder icons or localized folder names from untrusted sources. KB5094126 is important, as it fixes 200+ security bugs, but be careful, as it could cause havoc on some PCs.