diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9d1ec72..2eda155 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Exported `create_database`
 - In `DispatchChecker.interactive_dispatch_checker`, printed results are now sorted by runid.
 
+### Deleted
+
+- Extension package for InteractiveUtils
+
 ## [0.5.1] - 2025-01-23
 
 ### Fixed
diff --git a/Project.toml b/Project.toml
index 9054215..265ae8b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -21,7 +21,6 @@ Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 
 [extensions]
-PSBoardDataBaseInteractiveUtilsExt = "InteractiveUtils"
 
 [compat]
 Aqua = "0.8"
diff --git a/ext/PSBoardDataBaseInteractiveUtilsExt.jl b/ext/PSBoardDataBaseInteractiveUtilsExt.jl
deleted file mode 100644
index 210d0d6..0000000
--- a/ext/PSBoardDataBaseInteractiveUtilsExt.jl
+++ /dev/null
@@ -1,24 +0,0 @@
-module PSBoardDataBaseInteractiveUtilsExt
-
-export import_dataframe
-
-using PSBoardDataBase
-using CSV
-using DataFrames
-using InteractiveUtils
-
-"""
-    import_dataframe() -> DataFrame
-
-Import dataframe from clipboard.
-"""
-function import_dataframe()
-    file = tempname()
-    finalizer(file) do x
-        @async rm(x)
-    end
-
-    CSV.read(file, DataFrame)
-end
-
-end # module