Common Koinly Import Errors and How to Fix Them
Accurate transaction data is the foundation of stress‑free crypto tax reporting. Yet one of the most common frustrations crypto users face is importing their data into Koinly only to be met with errors, warnings, or confusing balances.
The good news? Most Koinly import issues are not tax problems, they’re data problems. And almost all of them can be fixed with a clear, systematic approach.
In this guide, we’ll walk through the most common Koinly import errors, why they happen, and exactly how to fix them, using a clear, practical framework designed to improve accuracy and confidence.
Key Takeaways
Most Koinly issues stem from data inaccuracies, not tax miscalculations.
Incomplete or duplicated imports distort cost basis and portfolio balances.
Transfers and DeFi activity require review to prevent incorrect taxable events.
Resolving warnings and balance discrepancies is essential before finalizing tax reports.
Why Koinly Import Errors Happen
Before jumping into fixes, it’s important to understand why errors occur in the first place.
Koinly relies on three things:
Complete transaction history
Correct wallet connections
Accurate labeling of transfers, trades, and income
When even one of these is incomplete or misclassified, Koinly will still calculate, but the results won’t be reliable.
Think of Koinly as a calculator. It’s powerful, but it can only work with the data you give it.
Error #1: Missing Purchase History
What you’ll see in Koinly:
“Missing purchase history” warning
Extremely high capital gains
Cost basis showing as zero
Why this happens: This occurs when Koinly can see a disposal (sell, swap, spend) but cannot see how or when the asset was originally acquired.
Common causes include:
Wallet imported, but exchange where you bought the asset is missing
Partial CSV imports
Using multiple exchanges over time
How to fix it:
Identify which asset is flagged
Check if the original buying exchange or wallet is imported
Import all historical data, even from years ago
If the exchange no longer exists, add a manual transaction with the correct cost basis
Pro Tip: Always import earliest data first, then move forward in time. This prevents cost‑basis gaps.
Error #2: Duplicate Transactions
What you’ll see in Koinly:
Inflated balances
Duplicate buys or sells
Unrealistic profit or loss figures
Why this happens: Duplicate transactions usually appear when:
You import both API and CSV for the same wallet or exchange
You re‑upload the same CSV multiple times
You connect multiple wallets that track the same activity
How to fix it:
Go to Transactions → Filters → Duplicates
Identify the duplicated source (API vs CSV)
Delete one data source, not individual transactions
Re‑sync and re‑check balances
Pro Tip: Use either API or CSV, not both, unless you clearly separate date ranges.
Error #3: Transfers Marked as Trades or Income
What you’ll see in Koinly:
Unexpected taxable events
Gains triggered on internal transfers
Income showing where none exists
Why this happens: Koinly doesn’t always know whether a transaction is:
A transfer between your own wallets
A trade
Income
If one side of a transfer is missing, Koinly may treat it as a taxable event.
How to fix it
Ensure both sending and receiving wallets are imported
Manually edit the transaction
Change the label to Transfer
Confirm fees are correctly assigned
Error #4: Incorrect Wallet Balances
What you’ll see in Koinly:
Negative balances
Assets you no longer hold still appearing
Wallet balances not matching reality
Why this happens: Balance issues are almost always caused by:
Missing transactions
Wrong timestamps
Failed API syncs
How to fix it:
Compare Koinly balance with the actual wallet or exchange
Look for gaps in transaction dates
Re‑sync the API
Upload missing CSVs if needed
Pro Tip: Fix balances before reviewing tax reports. Balance issues always flow downstream.
Error #5: Unsupported or Misclassified Tokens
What you’ll see in Koinly:
Tokens marked as “Unknown”
Tokens priced at $0
Incorrect market values
Why this happens: New or obscure tokens may not be fully supported, especially from DeFi protocols.
How to fix it:
Click the transaction and review token details
Assign the correct contract address if available
Manually set the fair market value if required
Label DeFi activity accurately (reward, interest, liquidity, etc.)
Error #6: DeFi Transactions Showing Extreme Gains or Losses
What you’ll see in Koinly:
Very large gains or losses
Complex transactions split incorrectly
Why this happens: DeFi protocols often bundle multiple actions into one transaction. Koinly may misinterpret these without manual review.
How to fix it:
Break down the transaction using a block explorer
Split the transaction inside Koinly
Re‑label each component correctly
Confirm cost basis and proceeds
Pro Tip: DeFi accuracy comes from review, not automation.
A Simple Checklist Before Finalizing Taxes
Before generating your tax report, always confirm:
All wallets and exchanges are imported
No unresolved warnings remain
Wallet balances make sense
Transfers are not taxed
DeFi and income labels are accurate
This single review step can save hours, and potentially thousands in incorrect tax calculations.
Conclusion
Koinly is one of the most powerful crypto tax tools available, but it’s only as accurate as the data behind it.
Rather than focusing only on which buttons to click, it’s far more important to understand how to review and interpret your data so you can confidently spot errors, correct them, and trust your reports.
If you want a step‑by‑step system for cleaning up your Koinly account, reviewing DeFi activity, and generating tax‑ready reports with confidence, a structured and methodical review process makes all the difference.
FAQs
1. Are Koinly import errors tax issues or data issues?
Most errors are data-related, not tax-related. Incomplete transaction history or misclassified activity leads to incorrect calculations.
2. Why is Koinly showing extremely high gains or zero cost basis?
This usually happens when purchase history is missing. Without acquisition data, Koinly assumes a zero cost basis.
3. Why are transfers or DeFi transactions being taxed?
When wallets are missing or transactions are mislabeled, Koinly may treat transfers or complex DeFi actions as taxable events.
Written by:
Andrew Harder
About me
Hi there 👋 I’m Andrew, with 10+ years in bookkeeping and 5 years in crypto, helping investors track and manage their portfolios with practical systems.
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