Whenever wabbajack failed the installation, first close wabbajack and simply try restarting wabbajack a second time.
If it still fails the installation, these are the most common issues:

Wabbajack is stuck on "Install configuration for Masterstroke"

1. Restart Wabbajack.
2. Click Browse Modlists, and select Masterstroke again.
3. Make absolutely sure that you wait for the image to load and show the Masterstroke logo.
4. After filling the install and download folder, wait a couple seconds before pressing the play button to start the installation.

Unable to download Skyrim_Default.ini

1. Open your Steam library
2. Right click The Elder Scrolls V: Skyrim Special Edition, and choose "Properties..."
3. Set Language to English

If that didn't resolve the issue try the next solution below

Missing game file Data_ccbgssse037-curios.bsa
(and other game files)

1. In your Steam installation folder for Skyrim, go into the Data folder
2. Delete Data_ccbgssse037-curios.bsa and Data_ccbgssse037-curios.esl
3. Open your Steam library
4. Right click The Elder Scrolls V: Skyrim Special Edition, and choose "Properties..."
5. Open the tab "Installed files"
6. Click on "Verify integrity of game files"

All downloads from Nexus mods failed

1. Open the settings in wabbajack.
2. Click logout for Nexus Mods
3. Click login for Nexus Mods
4. You might have to wait 10 minutes before you can retry.

Loverslab is stuck on "Download begins in seconds"

1. Go back to the main page by clicking on the modname in the menu at the top.
2. Click the green download button, and try downloading again.

Failed to download file from Loverslab

1. Make sure you're logged in at the top left of the page.
2. Download the missing file manually from the Lover's Lab Mods page.
3. Place the file in the download folder. Do NOT unpack the file.

If all mods are failing, download them manually or you could try the following that helped for some users:

1. Close Wabbajack
2. Make sure that the Masterstroke folder is NOT inside the Wabbajack folder.
3. Open the Masterstroke\downloads folder. Search for any .package files and delete them if they exist.
4. Press Windows + R, type %localappdata%, and delete the Wabbajack folder.
5. Restart your PC, then launch Wabbajack again.

Failed to download file from Google Drive:

Barbarian Bodypaints - Racemenu Body and Head Overlays for UUNP CBBE and Males.7z
and Community Overlays 1 - CBBE Male and Female Repackage.zip

1. Download the two files manually from the links in Step 2: Installation
2. Place the files in the download folder. Do NOT unpack the file.

Files are corrupted when hashing

1. Check that your drive isn't full
2. Delete the corrupted files, and restart Wabbajack.
3. If the files keep getting corrupted it's possible an antivirus is interfering.
   
   • Try adding your Wabbajack folder (where the executable is located) and your selected modlist installation location to exclusions in your antivirus of choice.
   • If you're using a 3rd party antivirus (such as AVG, Avast, BitDefender, Webroot, Kaspersky, Norton, McAfee etc.) it's likely that adding the folders to exclusions will not be enough and you may need to disable or uninstall your 3rd party AV as they can incorrectly mark files like usvfsproxyx86.exe (required for MO2) as a virus.
   • We recommend doing so anyway as Windows Defender is likely much better at stopping threats, according to data from av-test.org: https://www.av-test.org/en/antivirus/home-windows/.
   • If you still think a file is a virus, you can upload it to virustotal and get it scanned by multiple antiviruses. Here is a scan of usvfsproxyx86.exe, of which 2 antiviruses report a false positive: https://www.virustotal.com/gui/file/356c029b7bf0bed41460ceacf2c756560101b9b0977c349925d81d76392dd0c4/detection.

Modorganizer does not open and creates .dmp files

1. Install the c++ redist version listed as requirement in Step 1: Preperation
2. Restart your PC