diff --git a/src/cachefile.rs b/src/cachefile.rs
index 861aab7..9d0dba3 100644
--- a/src/cachefile.rs
+++ b/src/cachefile.rs
@@ -63,15 +63,7 @@ impl CacheFile {
                 bar: &ProgressBar,
             ) -> error::Result<()> {
                 bar.set_message(format!("checking {:?}", file.get_name()));
-
-                match file.check_hash(|bytes| bar.inc(bytes)) {
-                    Ok(true) => Ok(()),
-                    Ok(false) => Err(error::Error::unknown(format!(
-                        "Hash mismatch for file {:?}!",
-                        file.get_name()
-                    ))),
-                    Err(e) => Err(e.into()),
-                }
+                file.check_hash(|bytes| bar.inc(bytes))
             }
 
             info!("checking files in {state:?}");
diff --git a/src/error.rs b/src/error.rs
index 515f567..f636617 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -26,12 +26,15 @@ pub enum Error {
     #[error(transparent)]
     StdIo(#[from] std::io::Error),
 
-    #[error("response error: {0}")]
+    #[error("Response error: {0}")]
     Response(String),
 
     #[error("Invalid {0}")]
     InvalidParameter(Parameter),
 
+    #[error("Mismatch, expected {expected:?} but got {actual:?}")]
+    Mismatch { expected: String, actual: String },
+
     #[error("Unknown error: {0}")]
     Unknown(String),
 }
@@ -59,14 +62,18 @@ impl Error {
         Self::Response(into_string(e))
     }
 
-    pub fn unknown(e: impl ToString) -> Self {
-        Self::Unknown(into_string(e))
+    pub fn mismatch(expected: impl ToString, actual: impl ToString) -> Self {
+        Self::Mismatch {
+            expected: into_string(expected),
+            actual: into_string(actual),
+        }
     }
 
     #[must_use]
     pub fn is_fatal(&self) -> bool {
         match self {
             Self::InvalidParameter(p) => p.is_fatal(),
+            Self::Mismatch { .. } => true,
             Self::Unknown(_) => true,
             _ => false,
         }
diff --git a/src/file/checked.rs b/src/file/checked.rs
index 07688f7..92e9ef7 100644
--- a/src/file/checked.rs
+++ b/src/file/checked.rs
@@ -53,12 +53,9 @@ impl Checked {
         }
     }
 
-    pub fn hash(&mut self, f: impl Fn(u64)) -> io::Result<()> {
+    pub fn hash(&mut self, f: impl Fn(u64)) -> error::Result<()> {
         if self.hash.is_some() {
-            return Err(io::Error::other(format!(
-                "file {:?} is already hashed!",
-                self.path.display()
-            )));
+            return Err(error::Error::mismatch("unhashed file", self.path.display()));
         }
 
         self.hash = Some(super::compute_file_hash(&self.path, self.size, f)?);
@@ -101,7 +98,7 @@ impl<'t> FileTrait<'t> for Checked {
         self.size
     }
 
-    fn check_hash(&self, on_progress: impl Fn(u64)) -> io::Result<bool> {
+    fn check_hash(&self, on_progress: impl Fn(u64)) -> error::Result<()> {
         super::check_file_hash(&self.path, self.size, self.hash.as_ref(), on_progress)
     }
 }
diff --git a/src/file/mod.rs b/src/file/mod.rs
index f2df684..95436a8 100644
--- a/src/file/mod.rs
+++ b/src/file/mod.rs
@@ -2,22 +2,19 @@ mod checked;
 mod chunk;
 mod uploading;
 
-use std::{
-    ffi::OsStr,
-    fs,
-    io::{self, Read},
-    path::Path,
-};
+use std::{ffi::OsStr, fs, io::Read, path::Path};
 
 use base64ct::{Base64, Encoding};
 use blake2b_simd::Params as Blake2b;
 
 pub use checked::Checked;
 pub use chunk::Chunk;
-use log::debug;
+use log::{debug, warn};
 pub use uploading::Uploading;
 
-fn compute_file_hash(path: &Path, size: u64, on_progress: impl Fn(u64)) -> io::Result<String> {
+use crate::error;
+
+fn compute_file_hash(path: &Path, size: u64, on_progress: impl Fn(u64)) -> error::Result<String> {
     let mut file = fs::File::open(path)?;
     let mut hasher = Blake2b::new().hash_length(64).to_state();
 
@@ -36,9 +33,7 @@ fn compute_file_hash(path: &Path, size: u64, on_progress: impl Fn(u64)) -> io::R
     }
 
     if bytes_read != size {
-        return Err(io::Error::other(format!(
-            "Hashed {bytes_read:?} bytes, known file size {size:?}!"
-        )));
+        return Err(error::Error::mismatch(size, bytes_read));
     }
 
     let result = Base64::encode_string(hasher.finalize().as_bytes());
@@ -51,15 +46,20 @@ fn check_file_hash(
     size: u64,
     hash: Option<&String>,
     on_progress: impl Fn(u64),
-) -> io::Result<bool> {
-    let Some(hash) = hash else {
-        debug!("no hash to check for {:?}!", path.display());
-        return Ok(false);
+) -> error::Result<()> {
+    let Some(expected) = hash else {
+        return Err(error::Error::mismatch("hash", path.display()));
     };
 
-    let result = *hash == compute_file_hash(path, size, on_progress)?;
-    debug!("matches {:?}: {result:?}", *hash);
-    Ok(result)
+    let actual = &compute_file_hash(path, size, on_progress)?;
+
+    if expected == actual {
+        debug!("hash matches {expected:?}");
+        Ok(())
+    } else {
+        warn!("hash mismatch for file {:?}", path.display());
+        Err(error::Error::mismatch(expected, actual))
+    }
 }
 
 pub trait FileTrait<'t> {
@@ -80,5 +80,5 @@ pub trait FileTrait<'t> {
     /// get the file's size
     fn get_size(&self) -> u64;
 
-    fn check_hash(&self, on_progress: impl Fn(u64)) -> io::Result<bool>;
+    fn check_hash(&self, on_progress: impl Fn(u64)) -> error::Result<()>;
 }
diff --git a/src/file/uploading.rs b/src/file/uploading.rs
index 079317b..fec53b1 100644
--- a/src/file/uploading.rs
+++ b/src/file/uploading.rs
@@ -7,6 +7,8 @@ use std::{
 use log::warn;
 use serde::{Deserialize, Serialize};
 
+use crate::error;
+
 use super::{Checked, Chunk, FileTrait};
 
 #[derive(Serialize, Deserialize, Debug)]
@@ -101,7 +103,7 @@ impl<'t> FileTrait<'t> for Uploading {
         self.size
     }
 
-    fn check_hash(&self, on_progress: impl Fn(u64)) -> io::Result<bool> {
+    fn check_hash(&self, on_progress: impl Fn(u64)) -> error::Result<()> {
         super::check_file_hash(&self.path, self.size, self.hash.as_ref(), on_progress)
     }
 }
diff --git a/src/impl_ureq.rs b/src/impl_ureq.rs
index 1ffd188..99e083b 100644
--- a/src/impl_ureq.rs
+++ b/src/impl_ureq.rs
@@ -42,7 +42,7 @@ fn find_cause(
                 error.into()
             }
         }
-        error => error::Error::unknown(error),
+        error => error::Error::Unknown(error.to_string()),
     }
 }
 
diff --git a/src/output.rs b/src/output.rs
index b10d5e2..4d1bca9 100644
--- a/src/output.rs
+++ b/src/output.rs
@@ -3,7 +3,7 @@ use std::{fmt, process, sync::LazyLock};
 use console::{StyledObject, style};
 use dialoguer::{Confirm, Select, theme::ColorfulTheme};
 use indicatif::{ProgressBar, ProgressStyle};
-use log::{error, info};
+use log::{info, warn};
 
 type StaticStyled<'t> = LazyLock<StyledObject<&'t str>>;
 
@@ -95,7 +95,7 @@ impl Log {
     pub fn handle(e: &crate::error::Error) {
         if e.is_fatal() {
             // react to fatal error
-            error!("fatal error: {e:?}");
+            warn!("fatal error: {e:?}");
             Self::error(e);
         }
 
diff --git a/src/sharry/client.rs b/src/sharry/client.rs
index 517a40a..ddb914c 100644
--- a/src/sharry/client.rs
+++ b/src/sharry/client.rs
@@ -32,9 +32,10 @@ pub trait Client {
         {
             Ok(fid)
         } else {
-            Err(error::Error::unknown(format!(
-                "Could not extract File ID from {uri:?}"
-            )))
+            Err(error::Error::mismatch(
+                "<proto>://<base>/api/v2/alias/upload/<share>/files/tus/<file>",
+                uri,
+            ))
         }
     }