Symptom → cause → fix. If your case is not here, check the session log (%LOCALAPPDATA%\SimpleZipDrive\Temp\Logs\debug_*.log) — it names the exact failing step — and see Logging .
Symptom / message Cause Fix “Dokan Driver Not Found” dialogDokan not installed, or dokan2.dll not loadable Install Dokan v2 ; reboot if the mount still fails “Dokan Driver Incompatible” x64/x86 Dokan on an ARM64 system (architecture mismatch) Install the ARM64 Dokan build, or use the Dokan x64 package on x64 Windows “Dokan error: …” , retries “attempt 1/2” Transient driver failure Usually resolves on retry; if persistent, reinstall Dokan “WinFsp not found” dialogWinFsp missing Install WinFsp 2.1+ “WinFsp driver service is not running. Please start the WinFsp.Launcher service.” WinFsp.Launcher service stoppedsc start WinFsp.Launcher (admin) or restart via services.msc “WinFsp version mismatch: installed x.y, required 2.1. Mount blocked.” WinFsp older than 2.1, or interop/driver mismatch Upgrade WinFsp to ≥ 2.1 stable. 2.2.x betas are fine “WinFsp native DLL could not be loaded” Native driver DLL unreadable Reinstall WinFsp; check that no AV quarantined winfsp-x64.dll
Symptom / message Cause Fix “The mount point is already in use…” / 0xC0000035 + “Mount Point In Use” dialogLetter or folder claimed by another drive/process Pick a different letter/folder; subst-mappings and other virtual drives count “Skipping ‘M:' (already in use).” for all lettersM–Q all taken Mount to a folder, or free a letter “Error: Failed to auto-mount on any preferred drive letters.” Same Same 0xC0000034 “The WinFsp driver was not found or is not running” on a folder mount in versions < 2.9.0Historical bug: folder paths were misclassified as drive letters, so the folder was never created Upgrade to 2.9.0+ (fixed) 0xC000003A “The mount point path was not found” Folder path invalid Check the path 0xC0000022 “Access denied” Permissions on the folder Choose a folder you can write to “The path is empty” on every WinFsp mount in versions < 2.9.0WinFsp interop crashed inside the single-file bundle (Assembly.Location empty) Upgrade to 2.9.0+ — winfsp-msil.dll now ships beside the exe
Symptom / message Cause Fix “The file ‘X’ is not a supported archive” Extension not in the supported list Rename to the correct extension if it is a supported format; otherwise convert “Archive file not found at ‘…’” Path wrong / network share unreachable Check the path Password dialog loops, then “Mount aborted after 3 attempts” Wrong password Verify the password; cancelling stops the mount cleanly “The archive file appears to be corrupted, incomplete, or uses an unsupported format/feature” Broken download / unsupported feature Re-download; test the archive in 7-Zip; note that corrupt RARs are reported as corruption (not as password prompts) since 2.9.0 Specific entries unreadable, log shows “Decompression failed” / “SevenZip fallback also failed” Entry-level corruption or exotic compression Verify the archive; re-create it if possible “Insufficient disk space to extract file ‘…’” Temp volume full Free space on the drive holding %LOCALAPPDATA%
Symptom Explanation Action “A drive is already mounted. Please unmount it first.” One mount per instance Unmount, then mount again Memory appears to “double” the file size in Task Manager (versions < 2.9.0) Transient double-buffer during decompression Upgrade to 2.9.0+ ; also see Caching for the new single-buffer path High RAM after opening a huge file Entry cached in memory up to MaxMemoryPerFileMb Lower the setting to offload big files to the disk cache Leftover Temp\<pid>_<guid> folders after a crash Session died before cleanup Auto-swept at next startup, or use Clean Temp Files Empty folders in %LOCALAPPDATA%\SimpleZipDrive\Mounts Cross-integrity mount points are not auto-deleted Remove manually when unmounted Update check never appears Silent when offline, or you are already current Check the log line “Update check skipped: …” App closes instantly on unmount of large drives Watchdog force-exit if cleanup exceeds ~5 s Data is safe; temp files are swept next startup
Close the app (unmount first). Delete %LOCALAPPDATA%\SimpleZipDrive. If mount points stay broken, restart Windows (driver state resets). Still broken? Reinstall the driver (Dokan/WinFsp) and the app (Installation ).